The pedal inputs on the UX2 are for momentary switches only (like the keyboard sustain pedal used with a synthesizer or digital piano). They’re used to step up and down through presets or to control start/stop and other MIDI Machine Control functions. Wah/Volume needs to be controlled by an external MIDI source (like a programmable MIDI foot controller plugged into your computer’s MIDI interface). Complete details are in the help files.