It's not currently possible.
The issue is, MSFS has a bug ( or maybe an omission ) in the SDK, where the command to ask a key from the simulator in exclusive mode from Simconnect is not working, which means whatever key we use, the sim will receive it anyway, triggering its own function. This changed from FSX and P3D, where we could momentarily steal a key for exclusive use, then giving it back to the sim when we were done with it.
This doesn't give use much freedom to choose keys, because they only ones we can use are those that aren't used in the Showcase camera, or are used to do less used functions that might eventually be disabled, like focus blur.