This article covers the use of a FCB1010 running UnO firmware and one Boss FV500 as an extra expression pedal (connected via the pedal jack).

 

My goal was to set up the FCB1010 to work exactly the same in each FCB program, and use the Axe-FX patches to determine what happens with each pedal press (via scenes and external controllers), because it is much easier to program than the FCB.