[Exim] STMP virus filtering

SOS

Problem: some Windows clients have a virus that is forging emails.

Solution: Server side filtering - I am rebuilding our RedHat 6.x sendmail server with Debian Woody and Exim.

Is there a way to filter known virus like attachments before relaying
messages with Exim?

Are there any recommended programs I should look into ?

I would like to filter out known vectors:
    *.src
    *.exe
    *.doc
    *.src
    *.vbs

What should I look at the SMTP transport section in the exim.conf ?

Current Sendmail relay :
    uses /etc/mail/access  to limit relay access
    uses /etc/mail/relay-domains to define relay domains
    generic sendmail.mc with:
    MAILER(smtp)

I will be completing this task by days end.

Best Regards,

Theodore Knab
SysAdmin