Well, what you were trying here, seems not to make sense
for the "guys".
Music in pbo format sounds like an addon, but i'm sure
you just want to include custom music to your missions.
Therefore i suggest you to read the very first thread in
this section. It deals with implementing sounds/music into
your missions.
You can't expect that "guys" rushing into this thread, just
to write a complete tutorial for you, when it's already there
(two threads above)
~S~ CD