Long shot: Sustain pedal input could also support expression pedal?

[beaugunderson]

I'd love if I could plug an expression pedal into the sustain pedal jack and use that to send MIDI messages; I'm going to resort to using one of these for now:

https://www.tindie.com/products/beatbars/expression-pedal-to-midi-usb-adapter-ex2m/

Also the CAPTCHA is out of control in terms of difficulty, this is my fourth try...