Problem with From: Header without <> Character?, Please Help

Hello RT-List,

after migration to RT3, the Requestor gets no "autreply on create"
email, if the initial Email is coming from our online Store (a order
confirmation email with faked from adresses to the customer mailaddress)
In syslog i see “No recipients found. Not sending.”

When i do “echo Bla|mail -s test rt-queue@to-our-rt.de” all works fine.
The only Difference in the Mailheader i can see is the From: Line. The
Online Store sends order confirmations with no <> characters and real
Name in this line. Is a possible reason? If so, how can i go around
this? The Onlinestore is mandatory, i can not make any changes there.

My System is RT3.0.10 on Debian with perl 5.8.3.

Many Many Thanks for Your help!