Enter the name of your custom food as "Green Tea (8 oz.)." Then just enter that when you drink it; if you drink only 4 oz. at a particular time, enter .5 as your serving size in your daily log.
"If you drop an egg, you don't say, 'Oh, shoot' and drop the other 11, do you?"
-Source unknown, but obviously brilliant
Reached goal 4/16/2010...but kind of afraid to look these days