Headers appearing in body of mail?!

[Martin]

Hi,

I'm experimenting with an installation of Mailscanner + Clamav +
Postfix + SpamAssassin on Debian.

The machine acts as a gateway to our internal Exchangeserver. For some
odd reason, all mails get the following added to the body instead of
the header:

"X-MailScanner-Information Please contact the ISP for more information
X-ID-MailScanner: Found to be clean
X-ID-MailScanner-From: myemail at com
X-Spam-Status: No

testing...testing.."

I don't know where to start troubleshooting this issue. Any advice?

Thanks in advance.

Martin