Stubborn Doctor

I had gastric bypass surgery 20 months ago and have lost 100 pounds. I was just approved for a tummy tuck and mastopexy (breast lift) through my insurance company. My insurance co says that they will approve breast implants if they are medically necessary. My plastic surgeon now says that he does not think that he can submit my request for the implants because he doesn't believe this to be a "medical necessity", any ideas on what I can do or say to try to get him to help me with this. Or is there something that I am missing on what I shoud be saying to my doctor? I really feel helpless. I don't really want to have the lift done without getting the implants. I lost all of the fullness in my breast when I lost the weight and it sure is depressing to have to look at them now! Please help....anyone.... if you can. thanks