diff --git a/core/systems/ExtensionSys.cpp b/core/systems/ExtensionSys.cpp
index 88b6ea52..cd110370 100644
--- a/core/systems/ExtensionSys.cpp
+++ b/core/systems/ExtensionSys.cpp
@@ -41,14 +41,26 @@
 CExtensionManager g_Extensions;
 IdentityType_t g_ExtType;
 
-CExtension::CExtension(const char *filename, char *error, size_t maxlength)
+void CExtension::Initialize(const char *filename, const char *path)
 {
-	m_File.assign(filename);
 	m_pAPI = NULL;
 	m_pIdentToken = NULL;
-	m_PlId = 0;
 	unload_code = 0;
-	m_FullyLoaded = false;
+	m_bFullyLoaded = false;
+	m_File.assign(filename);
+	m_Path.assign(path);
+}
+
+CRemoteExtension::CRemoteExtension(IExtensionInterface *pAPI, const char *filename, const char *path)
+{
+	m_pAPI = pAPI;
+	Initialize(filename, path);
+}
+
+CLocalExtension::CLocalExtension(const char *filename)
+{
+	m_PlId = 0;
+	m_pLib = NULL;
 
 	char path[PLATFORM_MAX_PATH];
 
@@ -73,12 +85,27 @@ CExtension::CExtension(const char *filename, char *error, size_t maxlength)
 		g_SourceMod.BuildPath(Path_SM, path, PLATFORM_MAX_PATH, "extensions/%s", filename);
 	}
 
-	m_Path.assign(path);
-
-	m_pLib = NULL;
+	Initialize(filename, path);
 }
 
-bool CExtension::Load(char *error, size_t maxlength)
+bool CRemoteExtension::Load(char *error, size_t maxlength)
+{
+	if (!PerformAPICheck(error, maxlength))
+	{
+		m_pAPI = NULL;
+		return false;
+	}
+
+	if (!CExtension::Load(error, maxlength))
+	{
+		m_pAPI = NULL;
+		return false;
+	}
+
+	return true;
+}
+
+bool CLocalExtension::Load(char *error, size_t maxlength)
 {
 	m_pLib = g_LibSys.OpenLibrary(m_Path.c_str(), error, maxlength);
 
@@ -99,23 +126,24 @@ bool CExtension::Load(char *error, size_t maxlength)
 	}
 
 	m_pAPI = pfnGetAPI();
-	if (!m_pAPI || m_pAPI->GetExtensionVersion() > SMINTERFACE_EXTENSIONAPI_VERSION)
+
+	/* Check pointer and version */
+	if (!PerformAPICheck(error, maxlength))
 	{
 		m_pLib->CloseLibrary();
 		m_pLib = NULL;
-		snprintf(error, maxlength, "Extension version is too new to load (%d, max is %d)", m_pAPI->GetExtensionVersion(), SMINTERFACE_EXTENSIONAPI_VERSION);
+		m_pAPI = NULL;
 		return false;
 	}
 
+	/* Load as MM:S */
 	if (m_pAPI->IsMetamodExtension())
 	{
 		bool already;
 		m_PlId = g_pMMPlugins->Load(m_Path.c_str(), g_PLID, already, error, maxlength);
 	}
 
-	m_pIdentToken = g_ShareSys.CreateIdentity(g_ExtType, this);
-
-	if (!m_pAPI->OnExtensionLoad(this, &g_ShareSys, error, maxlength, !g_SourceMod.IsMapLoading()))
+	if (!CExtension::Load(error, maxlength))
 	{
 		if (m_pAPI->IsMetamodExtension())
 		{
@@ -126,13 +154,71 @@ bool CExtension::Load(char *error, size_t maxlength)
 				m_PlId = 0;
 			}
 		}
-		m_pAPI = NULL;
 		m_pLib->CloseLibrary();
 		m_pLib = NULL;
-		g_ShareSys.DestroyIdentity(m_pIdentToken);
-		m_pIdentToken = NULL;
+		m_pAPI = NULL;
 		return false;
-	} else {
+	}
+
+	return true;
+}
+
+void CRemoteExtension::Unload()
+{
+}
+
+void CLocalExtension::Unload()
+{
+	if (m_pAPI != NULL && m_PlId)
+	{
+		char temp_buffer[255];
+		g_pMMPlugins->Unload(m_PlId, true, temp_buffer, sizeof(temp_buffer));
+		m_PlId = 0;
+	}
+
+	if (m_pLib != NULL)
+	{
+		m_pLib->CloseLibrary();
+		m_pLib = NULL;
+	}
+}
+
+bool CRemoteExtension::IsExternal()
+{
+	return true;
+}
+
+bool CLocalExtension::IsExternal()
+{
+	return false;
+}
+
+CExtension::~CExtension()
+{
+	DestroyIdentity();
+}
+
+bool CExtension::PerformAPICheck(char *error, size_t maxlength)
+{
+	if (!m_pAPI || m_pAPI->GetExtensionVersion() > SMINTERFACE_EXTENSIONAPI_VERSION)
+	{
+		snprintf(error, maxlength, "Extension version is too new to load (%d, max is %d)", m_pAPI->GetExtensionVersion(), SMINTERFACE_EXTENSIONAPI_VERSION);
+		return false;
+	}
+
+	return true;
+}
+
+bool CExtension::Load(char *error, size_t maxlength)
+{
+	CreateIdentity();
+	if (!m_pAPI->OnExtensionLoad(this, &g_ShareSys, error, maxlength, !g_SourceMod.IsMapLoading()))
+	{
+		DestroyIdentity();
+		return false;
+	}
+	else
+	{
 		/* Check if we're past load time */
 		if (!g_SourceMod.IsMapLoading())
 		{
@@ -143,35 +229,33 @@ bool CExtension::Load(char *error, size_t maxlength)
 	return true;
 }
 
-CExtension::~CExtension()
+void CExtension::CreateIdentity()
 {
-	char temp_buffer[255];
-
-	if (m_pAPI)
+	if (m_pIdentToken != NULL)
 	{
-		if (m_PlId)
-		{
-			g_pMMPlugins->Unload(m_PlId, true, temp_buffer, sizeof(temp_buffer));
-		}
+		return;
 	}
 
-	if (m_pIdentToken)
+	m_pIdentToken = g_ShareSys.CreateIdentity(g_ExtType, this);
+}
+
+void CExtension::DestroyIdentity()
+{
+	if (m_pIdentToken == NULL)
 	{
-		g_ShareSys.DestroyIdentity(m_pIdentToken);
+		return;
 	}
 
-	if (m_pLib)
-	{
-		m_pLib->CloseLibrary();
-	}
+	g_ShareSys.DestroyIdentity(m_pIdentToken);
+	m_pIdentToken = NULL;
 }
 
 void CExtension::MarkAllLoaded()
 {
-	assert(m_FullyLoaded == false);
-	if (!m_FullyLoaded)
+	assert(m_bFullyLoaded == false);
+	if (!m_bFullyLoaded)
 	{
-		m_FullyLoaded = true;
+		m_bFullyLoaded = true;
 		m_pAPI->OnExtensionsAllLoaded();
 	}
 }
@@ -221,7 +305,12 @@ IdentityToken_t *CExtension::GetIdentity()
 	return m_pIdentToken;
 }
 
-bool CExtension::IsLoaded()
+bool CRemoteExtension::IsLoaded()
+{
+	return (m_pAPI != NULL);
+}
+
+bool CLocalExtension::IsLoaded()
 {
 	return (m_pLib != NULL);
 }
@@ -435,7 +524,7 @@ IExtension *CExtensionManager::LoadAutoExtension(const char *path)
 	}
 
 	char error[256];
-	CExtension *p = new CExtension(path, error, sizeof(error));
+	CExtension *p = new CLocalExtension(path);
 
 	/* We put us in the list beforehand so extensions that check for each other
 	 * won't recursively load each other.
@@ -456,13 +545,6 @@ IExtension *CExtensionManager::FindExtensionByFile(const char *file)
 	List<CExtension *>::iterator iter;
 	CExtension *pExt;
 
-	if (!strstr(file, "." PLATFORM_LIB_EXT))
-	{
-		char path[PLATFORM_MAX_PATH];
-		UTIL_Format(path, sizeof(path), "%s.%s", file, PLATFORM_LIB_EXT);
-		return FindExtensionByFile(path);
-	}
-
 	/* Chomp off the path */
 	char lookup[PLATFORM_MAX_PATH];
 	g_LibSys.GetFileFromPath(lookup, sizeof(lookup), file);
@@ -478,6 +560,16 @@ IExtension *CExtensionManager::FindExtensionByFile(const char *file)
 		}
 	}
 
+	/* If we got no results, test if there was a platform extension.
+	 * If not, add one.
+	 */
+	if (!strstr(file, "." PLATFORM_LIB_EXT))
+	{
+		char path[PLATFORM_MAX_PATH];
+		UTIL_Format(path, sizeof(path), "%s.%s", file, PLATFORM_LIB_EXT);
+		return FindExtensionByFile(path);
+	}
+
 	return NULL;
 }
 
@@ -513,7 +605,7 @@ IExtension *CExtensionManager::FindExtensionByName(const char *ext)
 	return NULL;
 }
 
-IExtension *CExtensionManager::LoadExtension(const char *file, ExtensionLifetime lifetime, char *error, size_t maxlength)
+IExtension *CExtensionManager::LoadExtension(const char *file, char *error, size_t maxlength)
 {
 	IExtension *pAlready;
 	if ((pAlready=FindExtensionByFile(file)) != NULL)
@@ -521,12 +613,11 @@ IExtension *CExtensionManager::LoadExtension(const char *file, ExtensionLifetime
 		return pAlready;
 	}
 
-	CExtension *pExt = new CExtension(file, error, maxlength);
-
-	/* :NOTE: lifetime is currently ignored */
+	CExtension *pExt = new CLocalExtension(file);
 
 	if (!pExt->Load(error, maxlength) || !pExt->IsLoaded())
 	{
+		pExt->Unload();
 		delete pExt;
 		return NULL;
 	}
@@ -790,6 +881,7 @@ bool CExtensionManager::UnloadExtension(IExtension *_pExt)
 		}
 	}
 
+	pExt->Unload();
 	delete pExt;
 
 	List<CExtension *>::iterator iter;
@@ -833,7 +925,7 @@ void CExtensionManager::MarkAllLoaded()
 		{
 			continue;
 		}
-		if (pExt->m_FullyLoaded)
+		if (pExt->m_bFullyLoaded)
 		{
 			continue;
 		}
@@ -891,7 +983,9 @@ void CExtensionManager::OnRootConsoleCommand(const char *cmdname, const CCommand
 					if (!pExt->IsRunning(error, sizeof(error)))
 					{
 						g_RootMenu.ConsolePrint("[%02d] <FAILED> file \"%s\": %s", num, pExt->GetFilename(), error);
-					} else {
+					}
+					else
+					{
 						IExtensionInterface *pAPI = pExt->GetAPI();
 						const char *name = pAPI->GetExtensionName();
 						const char *version = pAPI->GetExtensionVerString();
@@ -903,7 +997,9 @@ void CExtensionManager::OnRootConsoleCommand(const char *cmdname, const CCommand
 				}
 			}
 			return;
-		} else if (strcmp(cmd, "info") == 0) {
+		}
+		else if (strcmp(cmd, "info") == 0)
+		{
 			if (argcount < 4)
 			{
 				g_RootMenu.ConsolePrint("[SM] Usage: sm info <#>");
@@ -952,25 +1048,43 @@ void CExtensionManager::OnRootConsoleCommand(const char *cmdname, const CCommand
 			{
 				g_RootMenu.ConsolePrint(" File: %s", pExt->GetFilename());
 				g_RootMenu.ConsolePrint(" Loaded: No (%s)", pExt->m_Error.c_str());
-			} else {
+			}
+			else
+			{
 				char error[255];
 				if (!pExt->IsRunning(error, sizeof(error)))
 				{
 					g_RootMenu.ConsolePrint(" File: %s", pExt->GetFilename());
 					g_RootMenu.ConsolePrint(" Loaded: Yes");
 					g_RootMenu.ConsolePrint(" Running: No (%s)", error);
-				} else {
+				}
+				else
+				{
 					IExtensionInterface *pAPI = pExt->GetAPI();
 					g_RootMenu.ConsolePrint(" File: %s", pExt->GetFilename());
 					g_RootMenu.ConsolePrint(" Loaded: Yes (version %s)", pAPI->GetExtensionVerString());
 					g_RootMenu.ConsolePrint(" Name: %s (%s)", pAPI->GetExtensionName(), pAPI->GetExtensionDescription());
 					g_RootMenu.ConsolePrint(" Author: %s (%s)", pAPI->GetExtensionAuthor(), pAPI->GetExtensionURL());
 					g_RootMenu.ConsolePrint(" Binary info: API version %d (compiled %s)", pAPI->GetExtensionVersion(), pAPI->GetExtensionDateString());
-					g_RootMenu.ConsolePrint(" Metamod enabled: %s", pAPI->IsMetamodExtension() ? "yes" : "no");
+
+					if (pExt->IsExternal())
+					{
+						g_RootMenu.ConsolePrint(" Method: Loaded by Metamod:Source, attached to SourceMod");
+					}
+					else if (pAPI->IsMetamodExtension())
+					{
+						g_RootMenu.ConsolePrint(" Method: Loaded by SourceMod, attached to Metamod:Source");
+					}
+					else
+					{
+						g_RootMenu.ConsolePrint(" Method: Loaded by SourceMod");
+					}
 				}
 			}
 			return;
-		} else if (strcmp(cmd, "unload") == 0) {
+		}
+		else if (strcmp(cmd, "unload") == 0)
+		{
 			if (argcount < 4)
 			{
 				g_RootMenu.ConsolePrint("[SM] Usage: sm unload <#> [code]");
@@ -1141,3 +1255,29 @@ bool CExtensionManager::LibraryExists(const char *library)
 
 	return false;
 }
+
+IExtension *CExtensionManager::LoadExternal(IExtensionInterface *pInterface,
+											const char *filepath,
+											const char *filename,
+											char *error,
+											size_t maxlength)
+{
+	IExtension *pAlready;
+	if ((pAlready=FindExtensionByFile(filename)) != NULL)
+	{
+		return pAlready;
+	}
+
+	CExtension *pExt = new CRemoteExtension(pInterface, filename, filepath);
+
+	if (!pExt->Load(error, maxlength) || !pExt->IsLoaded())
+	{
+		pExt->Unload();
+		delete pExt;
+		return NULL;
+	}
+
+	m_Libs.push_back(pExt);
+
+	return pExt;
+}
diff --git a/core/systems/ExtensionSys.h b/core/systems/ExtensionSys.h
index 0816fb0c..1fe29f1c 100644
--- a/core/systems/ExtensionSys.h
+++ b/core/systems/ExtensionSys.h
@@ -59,13 +59,11 @@ class CExtension : public IExtension
 {
 	friend class CExtensionManager;
 public:
-	CExtension(const char *filename, char *error, size_t maxlen);
-	~CExtension();
+	virtual ~CExtension();
 public: //IExtension
 	IExtensionInterface *GetAPI();
 	const char *GetFilename();
 	IdentityToken_t *GetIdentity();
-	bool IsLoaded();
 	ITERATOR *FindFirstDependency(IExtension **pOwner, SMInterface **pInterface);
 	bool FindNextDependency(ITERATOR *iter, IExtension **pOwner, SMInterface **pInterface);
 	void FreeDependencyIterator(ITERATOR *iter);
@@ -79,14 +77,20 @@ public:
 	void RemovePlugin(IPlugin *pPlugin);
 	void MarkAllLoaded();
 	void AddLibrary(const char *library);
-private:
-	bool Load(char *error, size_t maxlength);
-private:
+public:
+	virtual bool Load(char *error, size_t maxlength);
+	virtual bool IsLoaded() =0;
+	virtual void Unload() =0;
+protected:
+	void Initialize(const char *filename, const char *path);
+	bool PerformAPICheck(char *error, size_t maxlength);
+	void CreateIdentity();
+	void DestroyIdentity();
+protected:
 	IdentityToken_t *m_pIdentToken;
 	IExtensionInterface *m_pAPI;
 	String m_File;
 	String m_Path;
-	ILibrary *m_pLib;
 	String m_Error;
 	List<IfaceInfo> m_Deps;			/** Dependencies */
 	List<IfaceInfo> m_ChildDeps;	/** Children who might depend on us */
@@ -95,9 +99,33 @@ private:
 	List<const sp_nativeinfo_t *> m_Natives;
 	List<WeakNative> m_WeakNatives;
 	List<String> m_Libraries;
-	PluginId m_PlId;
 	unsigned int unload_code;
-	bool m_FullyLoaded;
+	bool m_bFullyLoaded;
+};
+
+class CLocalExtension : public CExtension
+{
+public:
+	CLocalExtension(const char *filename);
+public:
+	bool Load(char *error, size_t maxlength);
+	bool IsLoaded();
+	void Unload();
+	bool IsExternal();
+private:
+	PluginId m_PlId;
+	ILibrary *m_pLib;
+};
+
+class CRemoteExtension : public CExtension
+{
+public:
+	CRemoteExtension(IExtensionInterface *pAPI, const char *filename, const char *path);
+public:
+	bool Load(char *error, size_t maxlength);
+	bool IsLoaded();
+	void Unload();
+	bool IsExternal();
 };
 
 class CExtensionManager : 
@@ -114,12 +142,16 @@ public: //SMGlobalClass
 	void OnSourceModShutdown();
 public: //IExtensionManager
 	IExtension *LoadExtension(const char *path, 
-		ExtensionLifetime lifetime, 
 		char *error,
 		size_t maxlength);
 	bool UnloadExtension(IExtension *pExt);
 	IExtension *FindExtensionByFile(const char *file);
 	IExtension *FindExtensionByName(const char *ext);
+	IExtension *LoadExternal(IExtensionInterface *pInterface,
+		const char *filepath,
+		const char *filename,
+		char *error,
+		size_t maxlength);
 public: //IPluginsListener
 	void OnPluginDestroyed(IPlugin *plugin);
 public: //IRootConsoleCommand
diff --git a/public/IExtensionSys.h b/public/IExtensionSys.h
index 3a7fe58c..9667095d 100644
--- a/public/IExtensionSys.h
+++ b/public/IExtensionSys.h
@@ -65,7 +65,9 @@ namespace SourceMod
 
 		/**
 		 * @brief Returns the filename of the extension, relative to the
-		 * extension folder.
+		 * extension folder.   If the extension is an "external" extension, 
+		 * the file path is specified by the extension itself, and may be 
+		 * arbitrary (not real).
 		 *
 		 * @return			A string containing the extension file name.
 		 */
@@ -112,6 +114,15 @@ namespace SourceMod
 		 * @return				True if extension is okay, false if not okay.
 		 */
 		virtual bool IsRunning(char *error, size_t maxlength) =0;
+
+		/**
+		 * @brief Returns whether the extension is local (from the extensions 
+		 * folder), or is from an external source (such as Metamod:Source).
+		 *
+		 * @return				True if from an external source, 
+		 *						false if local to SourceMod.
+		 */
+		virtual bool IsExternal() =0;
 	};
 
 	/**
@@ -142,10 +153,10 @@ namespace SourceMod
 		 * @return			True if load should continue, false otherwise.
 		 */
 		virtual bool OnExtensionLoad(IExtension *me,
-								  IShareSys *sys, 
-								  char *error, 
-								  size_t maxlength, 
-								  bool late) =0;
+			IShareSys *sys, 
+			char *error, 
+			size_t maxlength, 
+			bool late) =0;
 
 		/**
 		 * @brief Called when the extension is about to be unloaded.
@@ -166,8 +177,10 @@ namespace SourceMod
 		virtual void OnExtensionPauseChange(bool pause) =0;
 
 		/**
-		 * @brief Asks the extension whether it's safe to remove an external interface it's using.
-		 * If it's not safe, return false, and the extension will be unloaded afterwards.
+		 * @brief Asks the extension whether it's safe to remove an external 
+		 * interface it's using.  If it's not safe, return false, and the 
+		 * extension will be unloaded afterwards.
+		 *
 		 * NOTE: It is important to also hook NotifyInterfaceDrop() in order to clean up resources.
 		 *
 		 * @param pInterface		Pointer to interface being dropped.
@@ -199,27 +212,84 @@ namespace SourceMod
 			return true;
 		}
 	public:
+		/**
+		 * @brief For extensions loaded through SourceMod, this should return true 
+		 * if the extension needs to attach to Metamod:Source.  If the extension 
+		 * is loaded through Metamod:Source, and uses SourceMod optionally, it must 
+		 * return false.
+		 *
+		 * @return					True if Metamod:Source is needed.
+		 */
 		virtual bool IsMetamodExtension() =0;
+
+		/**
+		 * @brief Must return a string containing the extension's short name.
+		 *
+		 * @return					String containing extension name.
+		 */
 		virtual const char *GetExtensionName() =0;
+
+		/**
+		 * @brief Must return a string containing the extension's URL.
+		 *
+		 * @return					String containing extension URL.
+		 */
 		virtual const char *GetExtensionURL() =0;
+
+		/**
+		 * @brief Must return a string containing a short identifier tag.
+		 *
+		 * @return					String containing extension tag.
+		 */
 		virtual const char *GetExtensionTag() =0;
+
+		/**
+		 * @brief Must return a string containing a short author identifier.
+		 *
+		 * @return					String containing extension author.
+		 */
 		virtual const char *GetExtensionAuthor() =0;
+
+		/**
+		 * @brief Must return a string containing version information.
+		 *
+		 * Any version string format can be used, however, SourceMod 
+		 * makes a special guarantee version numbers in the form of 
+		 * A.B.C.D will always be fully displayed, where:
+		 * 
+		 * A is a major version number of at most one digit.
+		 * B is a minor version number of at most two digits.
+		 * C is a minor version number of at most two digits.
+		 * D is a build number of at most 5 digits.
+		 *
+		 * Thus, thirteen characters of display is guaranteed.
+		 *
+		 * @return					String containing extension version.
+		 */
 		virtual const char *GetExtensionVerString() =0;
+
+		/**
+		 * @brief Must return a string containing description text.
+		 *
+		 * The description text may be longer than the other identifiers, 
+		 * as it is only displayed when viewing one extension at a time.
+		 * However, it should not have newlines, or any other characters 
+		 * which would otherwise disrupt the display pattern.
+		 * 
+		 * @return					String containing extension description.
+		 */
 		virtual const char *GetExtensionDescription() =0;
+
+		/**
+		 * @brief Must return a string containing the compilation date.
+		 *
+		 * @return					String containing the compilation date.
+		 */
 		virtual const char *GetExtensionDateString() =0;
 	};
 
 	#define SMINTERFACE_EXTENSIONMANAGER_NAME			"IExtensionManager"
-	#define SMINTERFACE_EXTENSIONMANAGER_VERSION		1
-
-	/**
-	 * @brief Not currently used.
-	 */
-	enum ExtensionLifetime
-	{
-		ExtLifetime_Forever,			//Extension will never be unloaded automatically
-		ExtLifetime_Map,				//Extension will be unloaded at the end of the map
-	};
+	#define SMINTERFACE_EXTENSIONMANAGER_VERSION		2
 
 	/**
 	 * @brief Manages the loading/unloading of extensions.
@@ -235,26 +305,66 @@ namespace SourceMod
 		{
 			return SMINTERFACE_EXTENSIONMANAGER_VERSION;
 		}
+		virtual bool IsVersionCompatible(unsigned int version)
+		{
+			if (version < 2)
+			{
+				return false;
+			}
+			return SMInterface::IsVersionCompatible(version);
+		}
 	public:
 		/**
 		 * @brief Loads a extension into the extension system.
 		 *
-		 * @param path		Path to extension file, relative to the extensions folder.
-		 * @param lifetime	Lifetime of the extension (currently ignored).
-		 * @param error		Error buffer.
-		 * @param maxlength	Maximum error buffer length.
-		 * @return			New IExtension on success, NULL on failure.
+		 * @param path			Path to extension file, relative to the 
+		 *						extensions folder.
+		 * @param lifetime		Lifetime of the extension (currently ignored).
+		 * @param error			Error buffer.
+		 * @param maxlength		Maximum error buffer length.
+		 * @return				New IExtension on success, NULL on failure.
+		 *						If	NULL is returned, the error buffer will be 
+		 *						filled with a null-terminated string.
 		 */
 		virtual IExtension *LoadExtension(const char *path, 
-									ExtensionLifetime lifetime, 
-									char *error,
-									size_t maxlength) =0;
+			char *error,
+			size_t maxlength) =0;
 
 		/**
-		 * @brief Attempts to unload a module.
+		 * @brief Loads an extension into the extension system, directly, 
+		 * as an external extension.  
 		 *
-		 * @param pExt		IExtension pointer.
-		 * @return			True if successful, false otherwise.
+		 * The extension receives all normal callbacks.  However, it is 
+		 * never opened via LoadLibrary/dlopen or closed via FreeLibrary
+		 * or dlclose.
+		 *
+		 * @param pInterface	Pointer to an IExtensionInterface instance.
+		 * @param filepath		Absolute path to the extension's file.
+		 * @param filename		Name to use to uniquely identify the extension. 
+		 *						The name should be generic, without any 
+		 *						platform-specific suffices.  For example, 
+		 *						sdktools.ext instead of sdktools.ext.so.
+		 *						This filename is used to detect if the 
+		 *						extension is already loaded, and to verify 
+		 *						plugins that require the same extension.
+		 * @param error			Buffer to store error message.
+		 * @param maxlength		Maximum size of the error buffer.
+		 * @return				IExtension pointer on success, NULL on failure.
+		 *						If NULL is returned, the error buffer will be 
+		 *						filled with a null-terminated string.
+		 */
+		virtual IExtension *LoadExternal(IExtensionInterface *pInterface,
+			const char *filepath,
+			const char *filename,
+			char *error,
+			size_t maxlength) =0;
+
+		/**
+		 * @brief Attempts to unload an extension.  External extensions must 
+		 * call this before unloading.
+		 *
+		 * @param pExt			IExtension pointer.
+		 * @return				True if successful, false otherwise.
 		 */
 		virtual bool UnloadExtension(IExtension *pExt) =0;
 	};