Use midi CC or momentary switch as Aux button

I know that patch settings can assign actions to the pedal but I have not found any mention of assigning an external cc message to trigger the aux button or pedal action.

How can I address a CC message to trigger the aux button?

This is covered in section 3.4 of the manual:

Incoming “control change” messages using controller number 25 affect the internal status of the Aux button. A controller value between 64 and 127 simulates the Aux button being pressed down, while a controller value between 0 (zero) and 63 simulates a release of the Aux button.

Thanks. I thought I had (read)TFM, turns out I had (skimmed)TFM.