I was trying to mod the saint seiya music from euro to japan music and when I rip my japan copy, the game show up as a lot of DEMO_xx.usm under the movie folder. Any idea on how to proceed?
If the the European (PAL) version has the same files you can just copy the files and it might work. I suggest you make a backup of the game in case something goes wrong though.
Actually, my bad, I find the resource .cpk. I manage to find a program and extracted the file and found the sound folder. Do I just swap the euro sound folder with the japan sound folder and it should work? How do I repack the cpk?
Yeah just swap them, just make sure they both have the same file name and are around the same size though, somethime the JAP and EUR are "built" or made differently. The program you are using should re-pack the .CPK file, but if it doesn't you should be able to find a couple of programs that can repack .CPK files.