"Our
Stompboxes will work with any Expression Pedal that is a simple
resistive load (potentiometer) with a max value of 25kOhms. For the best
performance we recommend the Ernie Ball VP Jr. 25k.
Connect the Output to the Eventide Stompbox Expression Pedal Input. We
have also had success with the M-Audio MGear EX.P Expression Pedal.

Thanks!"

The visual volume pedal most likely does not meet this requirement.