I guess (never been using it) it doesn’t matter if it’s mini4L or complete. So Meine Box als 3D-Druck beklebt mit Stoff - #5 von Bernd2378 might be useful for your.
However, BUTTON_ACTIVE_STATE (0 to 5) is currently only part of settings.h which means, you’d need to compile your own firmware. But as we’re in transition to move everything (more or less) from settings.h to webinterface, this could als be moved in order of an upcoming patch. So custom firmware would not be necessary in that case.