You probably have all the information you need by now but let me add some information for you and others. I don't know who you have been taking to but you have gotten bad information. My two step sons joined the Military after getting their conditional green card in July, 2006. One joined the Marines in January, 2007 and the other joined the Navy in November, 2006. So you can join the Military with a conditional green card.
The Navy son applied for his citizenship in May, 2007 and took his oath and received naturalization in Septenber, 2007. The Marine son applied for citizenship in July, 2007 and has his interview in June, 2008.
The Military branch will help you file the N-400 and the N-426 applications. Under Presidental Executive order, anyone serving at least one day of active duty during periods of conflict (which we are now in) can apply for citizenship. This is an outstanding benefit for our Military members and well deserved. In fact, when you join the military with a conditional green card, they will ask you to sign a document that states you will apply for citizenship. You need citizenship to hold many security required jobs..
Good luck..
NatHug got a reaction from Penny Pincher in Expedited Citizenship through the Military?