Without spending a few minutes Googling with keyword phrases such as "Germanic naming conventions" "Germanic titles grammar" "Formal Germanic titles grammar" "German automobile documentation" etc. etc. I am GUESSING that this is a naming convention that, in essence, replaces the parenthesis, as in this example:
George (President) Bush
Bill (Rapist, Scumbag, Liar, National Embarrassment) Clinton
etc. (sorry about the second one, I couldn't resist). By doing things this way, the Deutsche equivalent of our Department of Motor Vehicles would be able to alphabetize everyone by name, yet retain evidence of a special title that is important to their identification. "Miss" , "Mister", etc. would not be the same sort of title as an honorary, elected or clerical title which would serve as a very specific identifier for a famous person. It would provide an additional means by which they could differentiate the then-Cardinal Josef Ratzinger from the ten thousand (or more) other Josef Ratzingers in Germany.
Again, this is just a guess and German Freepers, Freeper Linguists with a Specialty in Germanic Languages, and Freepers Who Simply Know More Than The Stoat are of course welcome to add to this explanation or to debunk it entirely if that's appropriate :-)
I hope that this might be of some help.
Not normally. I think it may be a Catholic Church thing in Germany to legally change the names of cardinals to have the title in the middle (a Fahrzeugbrief has your legal name on it). A professor with a doctorate (which is what Ratzinger was) would be referred to as "Prof. Dr. Josef Ratzinger" (and don't you dare leave the title out when referring to a Prof. Dr.), but I think his Fahrzeugbrief would likely just state "Josef Ratzinger." I've never seen a Fahrzeugbrief for a doctor, so I'm not too sure on that last bit. I could call one I know and ask, but calls to Germany are expensive on my phone plan.
It's a church thing. Bernard Cardinal Law was used in Boston and it has been this way during my long lifetime.