For dealing with the protein requirements check out:
I will say that it will be more difficult to remain truly vegetarian and hit the optimal macro-nutrient break down required by most anabolic diets. Due to the plant sources of nutrition you will have a harder time getting the needed fat and fat born vitamins. Your diet will tend towards too many carbs if you aren't careful.
For example, a common practice with anabolic diets is to remain low carb (no more than 125g a day) on your rest day, and then spike it after you work out. This gets the energy from the carbs going into the muscles to help feed recouperation. The diet on rest days is higher in fat and lower in carbs, and vice versa on training days.
The few vegetarian lifters out there either eat eggs and fish, or gained most of their strength before switching to a vegetarian diet. There are a few resources worth looking at:
The general consensus is that body building while a vegetarian will affect your progress. Usually it only means that it will take longer to get the same gains as your meat eating or even egg/fish eating compatriots. However, you will make those gains.