V.B.
J.,
My daughter was the same exact way....she would only take a sippy cup (and drink from it) if there was water in it-the minute she saw/taste it wasn't water, she refused and would only drink the milk from her bottle. What I did was take her water, and put an ounce of milk in it (essentially milky water) and every couple of days or so, I would up the ratio of milk to water, when in about 2 weeks (I believe) she was on 100% milk in her sippy cups-AND we have no problems switching back and forth from water to milk in her sippy cups-she takes them either way now.
Good luck~I understand the frustration, I was at my wits end until I tried at :-)