I have a Master-Lift garage door opener and I can't seem to program the transmitters for it. It is electronically programmed using a button on the receiver in conjunction with the buttons on the tranmitting units. When following the instructions, I am not getting the light indications that I am supposed to get to tell me that programming is successful. This whole problem started out when I decided to re-program the transmitters so I could get a different signal installed, since I lost one of my openers. Anyone out there have a clue as to what I'm doing wrong? Thanks for any help anyone can offer.