The bitsymuse ui tool didn't work for me either when I tried, and I've seen other reports of that - it does add the hack's code to your project but doesn't insert the music files. I ended up just following the instructions in the hack's code and editing the music in myself. Otherwise according to this topic it seems borksy could also be an option!
Thx for your respond! Did it work for you by doing it manually? Because borksy doesn't work either, unfortunately. But strangely, I've been able to add a single music for the whole game, even though it's not ideal .
