XeNTaX

I am trying to change some of the music for Bully: Scholarship edition, and have gotten as far as unpacking and converting all XWB/XSB files into WAV files, now i just need to know how to repack everything into something the game understands. there was a thread on here that explained it, but i found i very confusing and it missed some steps. if i could get a full tutorial on how to do this i would be very grateful