Vegetarian Restaurants in Orlando
In town are Ethos and Funky Monkey (table service restaurants) and Dandelion and Drunken Monkey (coffee/tea houses with food). Dandelion and Ethos are completely vegetarian (vegan, actually, in the case of Ethos) whereas the other two always have several vegetarian options. But they may be too far to drive if you want to stay close to the convention center.
Oops, I just recalled; Ethos has waiters but you place your order at the counter. So "table service" is misleading, sorry.