How exceedingly odd. Both the Touch and the PW access the US Kindle Store if the language is set to US English, and the UK Kindle Store if the language is set to British English (or at least mine do!). I wonder why Germany should be different in that regard?
Might it perhaps be worth contacting Kindle Customer Service and asking them?
Currently proofreading The Poison Belt, by Sir Arthur Conan Doyle.