I have solved this myself by using the below code rather than using AddSourceFilter function.
hr = CoCreateInstance(CLSID_LAV_SPLITTER_SOURCE, NULL, CLSCTX_INPROC_SERVER,
IID_IBaseFilter, (void **)&pLAVSplitterSource);
MessageBox(hwnd,L"ERROR - Could not create the LAV.",L"Error",0);
hr = pLAVSplitterSource->QueryInterface(IID_IFileSourceFilter,(void **)&pLAV);
hr = pLAV->Load(strFilename,NULL);
hr = pGraph->AddFilter(pLAVSplitterSource,L"LAV");
Now its created in both the formats what i was expected.