Normally at this point I would chide you gently for not reading the User Manual. But, to be fair, it is not quite as clear as it could be.
Look at Patching a Parameter to the Modulation Block’s “Modules” on page 40. it does not say so, but this approach can be used to remote almost any parameter on the unit.
To do what you want, go to LEVELS and press and hold the soft key under "wet/dry" until you see "< MODULATE".
Then press <MODULATE> to get to the modulation screen.
Turn the wheel to scroll through the controller options. Select "ext1" – unless this has been changed this will be driven by pedal 1.
Then if you plug a momentary foot switch into the pedal 1 jack, you will get full wet with the switch released, and full dry (bypassed) when it is pressed.
You can make further changes as described under "External Controllers" on pages 45-47.
