[crunch]

Here's how I did it:

I chose the music I wanted, took the .mp3 and named it "Amb_mymap.mp3". I then placed this file in my main>sound>amb_stereo folder.

Then I pointed to this file in my .mus file.

And Voila! The music played when I ran the map.

But--- I can't pack the music into the .pk3 file and have it work.
Here's exactly what the .mus file looks like:

path sound/amb_stereo

normal Amb_Verlassene_ext.mp3 // Plays over entire level
aux1 Amb_Verlassene_ext.mp3 // Exterior 1 - all exteriors
aux6 Amb_church.mp3 // Interior 1 - church interior
aux4 Amb_Verlassene_int.mp3 // house interiors

!normal volume 2
!normal loop

!aux1 volume 2.0
!aux1 loop

!aux6 volume 1.5
!aux6 loop

!aux4 volume 1.0
!aux4 loop


//Music Recommendation
//mus_09a_action.mp3

//Just in case we can get multiple ambiences working...
//normal Amb_Verlassene_ext // Player Start
//!normal volume 1
//!normal loop

The music works fine when I physically place it in the amb_stereo folder, but not if I try to pack it into the .pk3.