Living in a Navy town with lots of active duty and retired military personnel, I assumed all our PO would be savy about mailing pkgs overseas. I sent out the first three boxes at the main branch and had no trouble at all. (Love those FRB!) Today I stopped by a satellite branch due to time constraints; I wanted to get this box moving in the right direction now that it's packed. Big mistake. 
The postmistress admonished me that I couldn't use the "Attn: Any Soldier" designation anywhere on the pkg. I politely tried to point out that a specific soldier's name preceeded that, however she was adamant that it could not be used at all. Remembering what I'd read at this web site, I didn't argue with her (though it was difficult).
Then, she also said that I could not Redirect this to "Addressee's Commander" if undeliverable because the address itself might be messed up. I had considered using the phrase "Any local chaplain" as an alternate, however that doesn't account for a seperate address. What do other people do on their mailings?