Yeah, I had to reverse the polarity. The GEM Promega 3 senses the type of pedal at startup, though I doubt it senses polarity.
However, when looking at the continuous controller MIDI data, I never see any 0's. The lowest I get is a 4 out of the MIDI control range 0...127 when the pedal is fully released. And even that is not on a consistent basis, often I only get a 6 or 8. Is there any way to calibrate the continuous controller input using some GEM Promega configuration option?
Seems like I have to revert to switch mode unless someone can come up with a verified solution.