Exacty how would I hook up a drum machine to the PSR-550.. I went to our local music store today and checked out the new Zoom MRT-3, and wow what an awsome little piece it is too...

I'd love to sync this up with my 550.. I think doing this will satisfy my desire for better drum kits to record with. I completely understand how to hook it up from the MRT-3, but how would I set up my 550 to trigger it without triggering the keyboards preset styles.. I know you're supposed to be able to just use the start and stop button on the PSR, but how do I bypass the presets so that I can just use the drum machine for the drum tracks?
Thanks,
Squeak
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GEAR: Yamaha MOXF-6, Casio MZX-500, Roland Juno-Di, M-Audio Venom, Roland RS-70, Yamaha PSR S700, M-Audio Axiom Pro-61 (Midi Controller). SOFTWARE: Mixcraft-7, PowerTracks Pro Audio 2013, Beat Thang Virtual, Dimension Le.