problem - Logic pro 8 & Yamaha PSR-S500 keyboard - recording drums

Hi

I'm using Logic Pro 8 - with a Yamaha PSR-S500 music keyboard connected to my Macbook Pro via a USB cable (the keyboard came with drivers).

All "mono" instruments including piano record fine into Logic's arrange window. However when I want to record a "full drumkit" from the keyboard's Style options. (as if some is playing a full kit) I can record nothing.

I've gone to "mapped instruments" etc in the Environment window - all to no avail. is it because my music keyboard is not midi (ie with actual interface) or should I be checking something else?

DAVID
(Brisbane, Australia)