I think the best way would be Audiosurf making its own database from the scanned waveforms/tracks, not on basis of filenames. It would take some processing power but it can't be that much these days. If audiosurf can't find a match it should ask you which version you played, or by who this track is.. and then it compares waverforms so it can check that you don't cheat..
I think this is the most ideal but I don't know how hard this is to program.