Looking at some of the cockpit data output stuff, it looks like there is a value for "engine feather, beta, reverse thrust" that it can display. Loaded into the zibo to test it out. if thrust is forward this value is one, if I move the throttle to reverse it changes to 3. when I then move the axis all the way to max reverse, the throttle (actual) command increases. so all toto should need to do is watch for this engine feather beta reverse dataref to be set to 3, and then when this is the case, command reverse thrust as the throttle axis increases.