Wouldn't it be simpler to use the bin save / load thingy that was developed a while back to play MP3s. An external program could read the contents of an exported bin to allow for an unlimited amount of MP3s per level. All you'd have to do to play a song would be to use SetInv(player, bin, sound_number);
I've not used Xtension, but I'm guessing the number of MP3s is limited by the number of CD tracks since it wraps the CD playing call.
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