Needing Lexicon MPX-1 MIDI Program Change Advice

I have a Keith McMillen SoftStep-2 foot controller that runs through a MIDI Expander and into my MPX-1 (first of 2...I know the MPX-1 is a bit outdated, but they're my favorite). All I want the SoftStep to do is allow me to change programs on the MPX-1, and I can’t get the MPX-1 to respond. I’ve been at this off & on, literally, for weeks and ned to get it resolved.

I’m getting an LED flash from the SS2, set to transmit on Chanel 1, so I know it’s sending a MIDI signal.

My MPX-1 settings are:
MIDI Program Change: On
MIDI Receive: 1
MIDI Transmit: 1
MDI CTL Send: CC1 = CC1
MIDI CTL Smooth 100
MIDI Clock Send: Off
MIDI Automation: On
MIDI Sysex: On

The MPX-1 programs I’m trying to work with are above the presets range—201 & up.

I’ve scoured the manual but can’t find what it is I’m missing.

I could use some help, seriously… like a step-by-step, if possible.