Exim with Spamassassin and mimedefang

[Jeffrey N. Miller]

I want to setup a SMTP relay filtering SPAM and viruses.  The relay will relay the mail to my Exchange server.  Is there well documented HOWTOs on setting this up using Exim, Spamassassin, Mimedefang and a good virus scanning software?  I see HOWTOs using sendmail but I want to switch to Exim or am I just making things hard?