Cabin lights / Landing lights

Hi,

probably easy to solve, but i can't find any solution currently...is there a way for both AI aicraft and commercial products (i.e. Overland) to seperate cabinlight from landing lights, so that, when the landing lights are ON, cabin lights go OFF and vice versa.

I have already played with the alpha channel of the relevant *,_l.bmp, but either the cabin lights remain dark after landing lights are OFF or the cabinlights and landing lights are both together ON.

i want to simulate a dark cabin during langing/takeoff (OFF), but ON during cruise or while on ground.  

thanks for helping,

cheers,

harald