I'm not being patronising by posting this but have you tried in combat training.
Don't go into local mode though to look there's a bit of a problem with that and you can sometimes lose levels because of a glitch.
Also it only appears in the mosh pit in its own menu on the find a match screen.
Hope this helps.
This is not my game, it is my brother's game. He said it might be under multiplayer so we went to multiplayer, then local, then change game settings and it was there. We do not have paid Xbox Live. He does not know where combat training is either.
So is this map for multiplayer only and not zombies? As I said, we got this code from inside the box when he bought Black Ops 2.
Thank you guys for your help.