Indeed, you can use a form which is accepted in translation of commercial and legislative documents:

As soon as a complete German title appears, you translate it completely and give in brakets both complete and short German (e.g., German - Grm.).
Then in remaining text you might use either German abbreviation, or complete English title. Do not use English abbreviations instead of German ones if those English abbr, were not given in a certain OFFICIAL document or well-known dictionary.
ESCAPE footnotes or remark in translating official documents. Any translator footnote or remark in brakets might simply kill an official document! As far I know (after ten years of editing a scientific monthly), the situation is more tolerable only in translation of scientific artticles (in this case the translator might insert ONLY FOOTNOTES but never remarks in text).

Sincerely yours,
Dr. Tagir S. Tagirov
KSU.