saw that you have a vote for the in-game music on the homepage. Why not just have a directory for music files to go into so that you could play whatever you wanted to?
ps i am drooling at the prospect of playing stunts latest incarnation. keep up the good work.
You can play the files by downloading the correct version that you can play. You can also insert them into the game by downloading the ogg format version and copying it into the game's data\music folder.
I don't clearly understand your question though. CJP will answer it :) but right now I think he is on holiday or something similar because translations for the website aren't activated...
There is a directory somewhere in the Ultimate Stunts data that contains all the music. US will add the whole contents of that directory to its playlist. It supports OGG, MP3 and WAV files. I prefer to use OGG, because MP3 encoding technology is patented in some countries, and open source projects usually don't have the money to buy a license. (MP3 reading is not a problem AFAIK, but OGG rules anyway)