Germans using captured equipment (codes required)

[ciaphas]

As part of my never ending WW2 project i am about to embark on trying to build part of 16th Luftwaffe Division, however having never before purchased any of the russian equipment before i am wondering the following

does the gaz truck have the ability to take a german 2cm AA gun in the back (dont mind a little work) it comes with tilt I assume this is separate?
what is the code to use for the 12.2cm FH396(r) (122mm obr 1938)?
and the same with 76mm ZIS-3 gun (7.62cm FK288(r)) ?

thanks again
jon