I'm afraid that I didn't have time to read it in its entirety. The last time I discussed this issue with a German (~20 years ago), his impression was that you had to either: (a) belong to a shooting club; or (b) be able to prove that someone was actively trying to kill you. Even if he was fairly far off the mark, it's always been my understanding that getting permission to own a firearm in Germany is very difficult. I've known quite a few Germans who came to visit the US as exchange students and most of them had never even held a gun, much less fired one. Then again, most of them were too young to have done their military service, either.
I'm a lawyer, but I'm not your lawyer. If you need some honest-to-goodness legal advice, go buy some.