XeNTaX

So by far Parappa the Rapper is the only PSX game to use XA1 as an audio format. I decided that I wanted to try and edit the songs for a hack I'm doing for the game. So I've tried using an XA converter with a regular XA file and put in all the music files from the XA1 file I extracted with jpsxdec and replaced what the game uses for the "U rappin' Good" part of Stage 4 with an edited song. I then exported it as XA and renamed the extension to XA1 and replaced the XA1 from my ISO with the edited one. It sadly didn't work and my ISO won't work on PSX anymore. But that's beside the point. Has anybody ever successfully edited or replaced an XA1 file, and if you did, how did you do it?