ultra i notice you mentioned spaceships and spacestation, if i remember correctly (ubes will remind me if im wrong) but i got those into game for him, he then used them in his movie, so they are usable.
so my Question to you is have you inputted the mesh names to the ini files in the props folder, if not thats your problem.
reason there are some files that arent always sent because like my prop ini files include maybe 40-50 mesh names of files that i have/am worked/ing on so i wouldnt send those.