Volume pedal to control virtual organ

I occasionally have organists do overdubs in my studio, and alway use the virtual db33 plugin. Is there a volume pedal that exists, that could plug in to the computer, or midi interface and be assigned to control the volume of the organ? Even one that would control the volume of the track would work. Most b3 players really like performing with a their foot on volume pedal. Thanks!

Volume pedal to control virtual organ