L.B.
I'm sorry you are having to go through this! I saw an episode on Supernanny where a set of parents were having the same problem and what they did was make the changing of the bottle to a "special cup" an event. They talked to their son and let him know there was going to be a present for throwing the bottle away. Almost like a rite of passage. After he threw his bottle away then they went on a search for the "special cup". When he found the cup, it was wrapped up just like a present. It appeared to help him transition from bottle to cup.