Received: header and Mark Unscanned Message problem

[vg_us at hotmail.com]

Hello.

I have a problem delivering to one of the sites: mail gets rejected because 
"Not scanned: please contact your Internet E-Mail Service Provider for 
details" added to Received: header is not RFC compliant (according to that 
site's postmaster).
When I disable Mark Unscanned Messages and set "Unscanned Header Value =", 
mailscanner still inserts a "," after original header and my mail is 
rejected again.
Is there any way to make sure mailscanner doesn't touch Received: header at 
all?
I'm running version mailscanner-4.65.3-1 from rpm on centos5

Thank you
V