The ILogPlugin::GetConfig method is a private method and is used only for compatibility reasons to support rpc-based server interfaces from previous releases of IIS.
virtual HRESULT STDMETHODCALLTYPE GetConfig( IN DWORD cbSize, //the size of the log configuration object PBYTE Log //a pointer to the configuration information );
This is a private interface method used by IIS when it calls the built-in logging modules. Custom logging modules should return FALSE when this method is called.