as registered by law, a personal residence is not official

registered office
legal domicile
place of business

Schaefer/Wirtschaftswoerterbuch

in the UK, I would use "registered office"

of a notary, this is the term which is used in the agreements I translate EN>DE

Often "Amtssitz" is used for the combination of living quarters and official office for a high-ranking public official, like the White House, Schloss Bellevue, or 10 Downing Street.

http://www.vienna.cc/deutsch/hofburg4.htm

Heldenplatz
Die (neue) Hofburg, Amtssitz des Bundespräsidenten
Dieser Teil der Hofburg ist der Leopoldinische Trakt und beherbergt heute den Amtssitz des Bundespräsidenten.

http://www.vienna.cc/english/hofburg4.htm

Square Heldenplatz
The (new) Hofburg, Residence of Austrian president
This part of Hofburg is called the Leopoldinische Trakt and contains the residence of the Austrian president (Bundespräsident)

That is why many dictionaries show the term "residence" but "residence" would be nonsense for your context.

"Official office" is also often shown in dictionaries, but I would not use that unless a street address is given. To write that the "official office" is Kalamazoo would sound peculiar to me.

From the usage shown below, I would go for "official location" if forced at gunpoint to translate the term "Amtssitz",

http://www.admin.ch/ch/d/sr/172_010/a58.html

"Amtssitz des Bundesrates, der Departemente und der Bundeskanzlei ist die Stadt Bern."

In your context, however, it might be possible to leave it out and write something like:

"Registrar of Companies, Hamburg, Germany"

I will check the lowest possible confidence level as usual because I am almost always guessing. :-)

HTH

Dan