Sippy Cup Delimma

I have been trying for several months now to get Abby to drink her milk from a sippy cup and she just flat out refuses. She will happily drink water or juice out of any sippy, but as soon as she figures out milk is in there, she chucks the cup and starts throwing a fit. She will only drink her milk out of a bottle. I have tried almost every single sippy that they have out there and she couldn't care less about them. Now its so bad that the milk can only be in one particular bottle that she will drink it out of. I tried giving her milk in two different bottles today and yesterday, she takes on look at it and drops it on the ground. So I know how bad it really is. It's not that she just wants it in a bottle, it has the be the Avent one. So last night I was so fed up with it that I put her to bed without a bottle of milk because she refused to drink it out of her sippy. I tried everything and she would only take a few sips. Every time she did I would give her tons of praise to try to get her to realize that is what she is supposed to be doing but she still didn't care. I even put her to bed with the sippy which I never do and when I got it out after she fell asleep she had only drank maybe an ounce. So this morning I fed her breakfast and put a sippy of milk on her tray. She didn't even touch it. Then I put a sippy by her of water and she downed that. She even ate a ton more then usual at breakfast today, probably because she knows she's not going to get full from her milk. She is so stubborn and I am at my wits end. So if anyone has any suggestions I would love to hear them. I am going to try to get through this whole day without even showing her the Avent bottle. I guess she'll just drink water today.