Is it possible to change the bgm in an iso?

[Dart93]

So I'm playing through Dark Cloud (which is an awesome game btw), but the bgm gets really repetitive and annoying. So, I want to change the music files so I can put i something from Final Fantasy or Kingdom Hearts. Does anyone know how to do this?

This is the root directory of the iso:     and this is what's inside the Modules folder:    

[Livy]

1. No one knows where the soundtracks are stored.
   
2. No one knows what format they use.
   
3. No one knows how to re-bundle the file after changing the music files.
   

Everything is possible, assuming that you're a talent hacker.