Autoresponse-mail is not well formatted

Hallo all,

I have a problem with mail that is automaticly send from rt2.0.
There is one headerline:

Content-Type: text/plain
that should be
Content-Type: text/plain; charset=iso-8859-1

The template is configured as a autoresponse template,
via web interface.
Is there a possibility to change this headerline?

Thank you for your help
Kai Habighorst
pelion XII AG
Pelikanstr. 7, 30177 Hannover
Fon: [0511] 64 64 47 0
Fax: [0511] 39 13 07