Ampeg V4.com

so i have a distortion era vt22. just got it all worked on and whatnot. anyways i found one of the old ampeg issued 'reverb' switches, i plugged it into the back expecting to be able to click on and off the reverb. however i discovered that it actually operates the distortion...which i kinda like..for what im using it for...however is there a way to footswitch the reverb...would the old pedals with 2 buttons make a difference or is it just all in the knob? thanks