Try giving it to her cold, like you would anything else out of a sippy. If she doesn't want it, stop giving it to her and let her just have water. Believe me, it is WONDERFUL to have kids who love drinking PLAIN WATER. And SOOOOO much healthier for them than training them to fill up on calories in their beverages (milk, juice, soda, etc). My daughter, who is now almost 9 still doesn't care for soda, and it's fantastic for her health- the teeth especially - the acids in the soda are disastrous for teeth! My son didn't start drinking any soda until he was about 8 or 9 years either, and we limit him to one per day, max. And that is only a couple times a week, if then.
Let it go. Give her other healthy ways to take in calcium (dark leafy greens anyone?), and let her drink her water to her heart's content.
Just my 2¢.....