Hi Mike,
There are scripts that would probably be helpful to compare what you are doing to. This thread discusses them: http://ez.analog.com/message/129349#129349
What display are you using? What does it say?
Generally, if there is 3V on the output then it's sending video. That doesn't mean the TV can display it.VGA should be CEA format 1 if you are matching the timing/polarity of it. The ADV7513 has a register which tells you what CEA format it thinks you are sending (0x3E). This is described from page 34 in the programming guide.
Dave