[exim] ... ACL: BAD HEADER Non-encoded 8-bit data

Hello *,

my logfile shows

2008-03-19 23:01:17 1Jc6LV-0006Ly-OV F=<********@T-online.de> rejected
by non-SMTP ACL: BAD HEADER Non-encoded 8-bit data (char E4 hex): Date:

The Date: contains a German Umlaut.

How to accept it anyway?

--Frank Elsner