Hi DarkStar,
I wouldn't say that the pedal wiring is the wrong way around.... here's why
Generally an expression pedal is of two types. Type 1 sends reference voltage through the ring and receives varied voltage through tip while the type 2 sends reference voltage through the tip and receives varied voltage through the ring of the TRS connector.
The Bespeco vm18l pedal is of type 1. And the irig keys accepts only type 2.
The reason why this pedal worked with any other keyboard is because the firmware in most keyboards support either type pedal since it can sense the supply voltage and send cc accordingly. This feature is not available in irig keys IO 49 yet.
The rotation inverter switch swaps the ground and the reference voltage which will enable the pedal to either go from 0-127 or 127-0.
Some mistake the switch to swap the tip and ring as in a polarity switch in a balanced connector...
I rewired the pedal to swap the tip and ring. And it works perfectly on both polarities. 0-127, 127-0.