Start of episode says i need german uniform but it will not let me take it

I don't remember, maybe you have to kill, using a knife, a german soldier, so it's not showing bullet holes..

Knifing is no good either: the uniform must be bloodless. You'll need to force someone to surrender. Also get matching headgear and don't carry an allied rifle. Anything in your pockets does not matter. It is in the manual.

In the Whiskey Bar mission though, you get two German uniforms as starting equipment.