Sadly german uniforms cannot be chosen by players in coop. Theres a way around with tables but i conisder that as cheating and won't explain any further.
Here you can add/change/remove the enemies equipment for each missions: weapons, uniforms, helmet, items. Also tanks ammunition.
If you have no interest in modding you don't need to worry about. If, you may read about the structure of the file
on our wiki here
mpscripts.dta mpmaplist.txt ..was too early in the morning sorry
Defines which items, weapons, uniforms, .. can be choosen by the player himself.
Let's say you want the shotgun be availabe to choose in a mission (e.g Africa1)
Open mpmaplist.txt with any text editor of your choice, search for the Africa1 code part
and add following line:
<ITEM item_id="23" item_num="1" ammo_num="10"/>
23 is the item code for the shotgun, item_num sets the amount of how many shotguns can be chosen (by default it's one, you cannot carry more then 2 weapons anyway)
And ammo_num sets the amount of clips available. As written before axis equipment can't be chosen in coop besides the german knife.