i think i got it work the way I wanted (at least on the Milviz PC-6). The magic key is called TOGGLE THROTTLE REVERSE THRUST. it work like this:
- throttle axis to idle and land
- press TOGGLE THROTTLE REVERSE THRUST
- increase throttle axis
- reverse thrust engaged
This set of actions actually continues moving the throttle handle in the simulator backwards into reverse range using your throttle axis. Pressing it again reverses it and the throttle goes back forward.
Now not sure if this works in other turbo props or jets, but HUZZAH!