App-V MP for OpsMgr 2007 only supports version App-V 4.5 or later and does not support MOM 2005
Per the App-V blog:
The newly christened OpsMgr 2007 MP only supports version 4.5 App-V servers; it does not support previous SoftGrid server versions and does not support MOM 2005.
The MP is only available on Connect right now, but should be made publicly available soon.
Read more about the MP: