Sounds to me like KN is correct. The only way to hear the module voices is to play the midi throught the mod. (1)You can record or copy separate midi tracks so that, for example, trk 1 -8 play on your PSR and trk 9-16 play through your module. (2) You can have all tracks play thru both sources.
There are some programs that say they can record a .wav from a .mid, but I have never tried that. The easiest way to get a song into .wav format is to audio record it as you want it onto a digital or tape recorder and upload it to your PC.

------------------
Cass Pawlowski - Motown
PSR2000, SC88, Cakewalk