The Roland PK5 and most other midi bass pedals can play polyphonically, so you could play two-note chords with your feet. Sending that info to the bass section of the MidiJay would probably result in a chord of your choosing as long as the MidiJay recognizes the notes.

BTW - I have a great set of MidiStep pedals made by Fast Forward Systems (Hammond/Suzuki) that I'm about to put up for sale. If you're interested, email me.

And if Donny or someone else will refresh my memory, I'll put up a couple pics.