I've never tried it, but with the right wiring, it should work. The switch would have to be custom made, we don't make them. It would be limited - you couldn't have an LED on the switch, for example. You could simulate an IA button using the expression pedal switch actions, although it would not have all of the IA button features like groups, update on preset change, etc.
To build it, a momentary switch would need to be connected between the ring and sleeve of the expression pedal jack, and a 10k resistor would need to be connected between the tip and ring of the expression pedal jack.