Well,
As much as I want to help, I don't know much about PSR keyboards.
Do try http://www.synthzone.com/cgi-bin/forumdisplay.cgi?action=topics&number=37&SUBMIT=Go

Those guys really know their stuf. Mind you some of them hang out here as well. I just think that if you post right at the General Arranger section you'll get a lot more replies.

-ED-