[Mimedefang] Problem with Spamassassin

[Urs Köster]

Hello,
In my company we want to use Spamassassin on our sendmail servers (running SUSE), so I have installed MIMEDefang as an interface between the two. Mail gets processed correctly by MIMEDefang as the "X-Scanned-By: MIMEDefang 2.35" signature appears in the messages, but Spamassassin is not invoked as it should be from the standard mimedefang-filter I am using. 
Are there any additional configurations I have to make, e.g. do I need to have spamd running or do I need to tell MIMEDefang the spamassassin path somewhere?

Regards,
Urs Köster