I just discovered that sustain pedal only works on the 1st selected channel. If multiple channels are "lit" and receiving MIDI just fine the sustain pedal will only work on the first "lit" channel. If only a single channel is "lit" then the sustain pedal will work on that channel. I tested with two MIDI keyboard / sustain pedal combinations with the same result. I think I'm running Beta 2, but I didn't see anything in the release notes about sustain so I didn't bother trying a later version.
P.S. this is the weirdest damn implementation of MIDI channel assignment I've ever seen. ...sigh. You are gonna get ripped in reviews if you don't change it. But thanks all the same for implementing something. I hope you can work out the sustain pedal bug before release.