I think Skipper has hit on something and izi it needs to be applied to your question, although you have already thought of this I am presuming. to get the whole picture of his FLAK unit in very brief details or however it may be covered and should be locked in the Freiburg Archiv file.

of course another possibility and I personally have not tried to access them yet is the archiv's at Aachen and the Bundesarchiv in Berlin. maybe just maybe the info could be hiding here as well........ ?