Hi Rudi,
The Volume Pedal input is essentially a master volume for the entire instrument and cannot be re-assigned.
I would suggest you get a GEM Multi-Pedal which has 6 footswitches that can be assigned to Style Control functions, Sustain, Rotary Speed Control, etc. The Multi-Pedal only uses one pedal input so you still have two more that can be used for an Expression pedal and maybe another Multi-Pedal if you need to control that many functions with your feet.
Best Regards,
Dave
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Wm. David McMahan
Nat'l Product and Support Manager
Generalmusic USA
GEM Community Forums