[exim] LDAP/AD BindDN with umlaut

Hi guys,

how do I have to encode a dname for binding to an active directory
containing a german umlaut? I don't get this bastard to work.
Authenticating exim against the ad using a dname without umlauts works
perfectly fine.

I am using the recipe from the wiki:
http://www.exim.org/eximwiki/MsExchangeAddressVerification


Anybody any idea?

Patrick