I doubt they will warrenty it. I called about a messed up X9 body and they basically said no but that I could try a warrenty through a local shop. How did you break it? Theres a dude on my team who just broke a carbon cage too. He said it just went "SNAP" and broke without hitting anything. I'm not sure if its the same for the XO but with my X9 only the short cages are replacable.
if you have a receipt, bring it to a shop, theyll send it to sram and warantee it, i think it mught be a year or something... if they dont warantee it, then the man just got you down...
Ouch. Well I guess I'll just stick to X-9 for now.
I would try to warranty it. That looks like a manufacturers defect to me... go to your LBS and start complaining about "safety issues" and "catastrophic failure" and they will usually put a fire to their asses to get it warrantied.