Passenger cabin lights(for POSKY)how to add them.

Hello AllI have a number of POSKY 737/700s and they are excellent BUT! i notice when night flying that although you get cockpit lights,there are no passenger cabin lights.Strangely my VA(Euroharmony)use the 737/800 (also by POSKY)and this DOES display cabin lights.I took the aircraft CFGs from both models to see if i could get a clue there,but they both appear to be the same.So if anyone knows how to add cabin night lighting to the POSKY 737/700S I would appreciate it if you could tell me how to do it.cheers Andy