I've accually been wondering how to do this for quite a long time now.
Okay, I'm currently using the unregistered TK2 to make The Blade of Champion, and because it can't play MP3s, it can't play WAV files either! And I know it's possible, because I saw it happen in other games in unregisted TK2 without having to play it in #MidiPlay()?!!11one
P.S. Please don't make fun of me for asking this. I'm still sorta getting used to the loops and varibles of RPG Code. lol