I ran across this thread when looking at the AV options for Zimbra. I'm coming from Sendmail/MailScanner/MailWatch, so I'm used to a bit more control and visuals.
Some questions for anyone that has followed these directions:
1) Does it work?

2) Can you then archive and view spam logs with MailWatch?
3) How could I link it to the "junk/not junk" buttons within Zimbra?
If anyone has any ideas on these, I'd like to hear them!