This (wrong) info has been on the bmi website for a long time. As it has been reported to them (also via Amex) for several time, I thought they would have corrected it.

I had a couple of emails and calls to Amex Germany and UK about it and bmi is definitely not a partner of the German Amex MR program.

The only way is to apply for a UK Amex (with a UK adress and bank account) and talk them into transfering your German MR points into that new account. It should definitly work with the special foreign funds Amex that you also can get as a German and which participates in the UK MR scheme. But this one is expensive and you need a bank account in US$ or GBP (although it can be a german account). The points transfer is probably a once only possibility then.