The athor of the thread probably won't care by now, but I thought this shouldn't be left unanswered..
If you want to do this and aren't interested in details, you can just copy the contents of attached file to your game directory and you should be done.
Changing the menu theme to
BG1 one is indeed an easy thing to do:
The game music is stored in .acm, and you have to replace the original files, copying to override won't do. If you have the song in .wav, you can use '
DLTCEP' to convert it to acm.
ToB menu music is a single track, while
SoA has 4 tracks with the first one playing once and the others looping. You can change area/menu playlists by editing their
.mus files, in this case theme.mus for
SoA menu and for themet.mus for
ToB menu.