Does it work if you specify your country as "Germany" but give an Austrian address, postal code, etc.?
I realize that they are not the same country and that this has historically been something a point of contention, but I often see automated systems that can manage to process a Canadian address with country "U.S." or an American address with country "Canada" (usually Canadian people working around brain-dead online order systems) and I wonder whether that might not work here.