You'll find the team invitation list here
http://www.usfirst.org/roboticsprogr...uper-regionals
"How can I sign up for a Super-Regional?
Teams must qualify to attend Super-Regional events through their performance at a regional Championship event. Eligible teams will receive an invitation with registration instructions after their state or regional Championship. See below for details on the advancement criteria."
I guess if you didn't receive an invitation then you can't compete at a Super-Regional.