LED feedback momentary / toggle

I am a bit confused about the use of led feedback within CSS device parameter mapping . I manage to get them to work as I want with reactions but I am not sure I understand the parameter mapping options.
In this simple script, for example , I have tried several options. (tone that I have the button set as momentary on/off in the controller script) and all the various attempts I made in the mode selector mapping to get the button LED to turn on when pressed and off when unpressed did not work. Similarly I have problems in using button as toggle in device parameter mappings. I have a custom made controller that only output midi cc at value 127 when pressed, whilst my launch control produces 127 when pressed and 0 when unpressed. I am struggling to understand how to set up the device parameter mapping. for both.