my nektar nx-p doesn't work w/ my hx stomp, I've tried using the TRS direct, and splitting the T and R separately, updating the global settings each time, and trying both positions of the polarity switch. I am able to make switches work, but I can't get this expression pedal to do anything! grrrrr...
I don't know how this worked for Jonathan, but in my case, the NX-P resistor is between the T and R, but the HX Stomp wants it between the T and S (exp1) or R and S (exp2). Once I modified my cable (NX-P Tip--> HX Stomp Tip, and NX-P Ring--> HX Stomp Sleeve) then it worked.