You can do a workaround that essentially bypasses the Wah, even though it's "on". Then you can assign EXP1 to a different effect.
Select the Wah. click the both page buttons at the same time. click the bypass / control button.
set the following - using the knobs:
parameter = bypass switch = none
parameter = position controller = exp1 min value = 0 max value = 100
parameter = mix controller = exp1 min value = 0 max value = 0
parameter = level controller = none
now when you click the toe switch by pressing down on the volume / wah pedal, you will turn on the exp1 pedal with a completely dry mix so the Wah is gone.
This will allow you to go to any effects parameter on any of the other effects and assign exp 1 to control it without the Wah sound getting in the way.
