Nats recognize need for catching depth

http://washington.nationals.mlb.com/news/article.jsp?ymd=20090922&content_id=7099100&vkey=news_was&fext=.jsp&c_id=was

Have the Nats added anyone besides Jaime Burke?  I see Burke and Derek Norris are the only two invited to camp thus far as non-roster invitees.  Have the Nats brought in any six year free agents, or others to add to the overall depth in the system.  What if Pudge gets hurt before Flores is ready, then who gets the call?  Did Pete Orr learn the trade of catching over the winter so he can qualify as an emergency catcher?  What is the status of the Nats catching core after Pudge/Flores?