Mustang 1-1

Hey guys, I have a real F-16C block 50 hotas. Stick and throttle grip work fine, but the throttle arm runs a potentiometer which is basically a slider axis. I am able to use the afterburner detent automatically but how do I use the Idle cutoff. In BMS there is a button that sets it but in dcs I can't figure out how. I know you need a physical button press to trigger it but can you do it some other way? Thanks!!!