Steam > Steamapps > common > AI War 2 > GameData > Configuration > Music
That'll show a file with a list of all the tracks ingame. Judging by the "filename" bit, that's basically pointing it to where the music is. Those bits are hidden I believe, so you can't grab the music out of it (but you can buy it - the game doesn't have all of them anyway).
Just make it point to a file of yours, and I imagine it'd work.