We use a third party spam blocker. It does a better job than zimbra/spamassassin/amavis is doing, and incorporates some other methods of spam/ham determination. I have managed to hide the junk/not junk buttons in order to avoid user confusion.
I would like to be able to have the junk/not junk buttons forward the message to junk/not junk email addresses in addition to the default behavior.
Not sure how to proceed here, and where the existing code for this functionality might be living.
I would prefer to do this as a zimlet or other modular fashion to avoid breakage due to software upgrades.