“Select for FS control” assignment from the FSUIPC interface does not work!

[SMN204]

The “Select for FS control” assignment from the FSUIPC interface does not work!

The same assignments of the native bindings in the Conrtrol options in MSFS works!

[John Dowson]

Many FS controls work when assigned internally but not when assigned externally - this has been reported to Asobo (a very long time ago...).
You need to determine what works for the aircraft you are using. for example, for the Asobo King Air, there are presets:
    KA Fuel Left Condition Lever Low Idle
    KA Fuel Right Condition Lever Low Idle
However, I do not see anything similar for the Black Square King Air. You will need to investigate to determine how this can be assigned. As I don't have this aircraft, i cannot really advise, but you should start by looking at any available Input Events and lvars. You can use FSUIPC's logging facilities to investigate these.

You can also ask on the MobiFlght discord server (msfs2020 channel) if anyone can define a preset for you for this - that is the home of the community-driven effort to discover and publish presets for MSFS2020.