Loving my Wonderlove, and I'm having problems with the expression pedal setting. I'm using a DVP4 (Dunlop Mini Volume) as the expression pedal. ... which doesn't work, no matter what I've done. There's no change to the sound regardless of what position I have the expression pedal in, and (seemingly) regardless on what changes I made to the switches inside the pedal as well. Has anyone used this combo successfully - and does anyone have a clue what I might be doing wrong?