On/off Shim

I was trying to get my pi to turn on and off safely with the on/off shim using a relay controller that detects voltage from a second power supply. the problem is that it then makes the shim button on or off and not behave as a momentary switch. Is there a way to change the button to behave as either on or off? ie circuit closed turn pi on, circuit open safe shutdown.

I wouldn’t think its easily doable, if doable at all? Currently its short press on, long press off. You’d have to change the way the installed daemon works.
After the Pi boots up and the on off shim daemon loads, it watches for a signal from the button on one GPIO pin. If it gets the shutdown signal it shuts the OS down then sends a signal back on another GPIO pin to kill the power.