SYMPTOMS: Spamayes classifies mails before they get processed by any Outlook rule, or in the middle of Outlook's rules. This can be annoying, for example if you try to sort mail, that look like spam but isn't - e.g. many mailing lists will be classified as spam. The solution is to use SpamBayes' background filtering option, and implement a 'whitelist' of sorts.
WORKAROUND: There is a very nifty workaround (especially with Outlook) to do this:
Find the option "filter timer" in the advanced tab of your SpamBayes Manager dialog (in the drop-down menu from the SpamBayes toolbar). If you set up a delay of 2 seconds and an interval of one second, Outlook is able to apply a mailbox rule to this item. This is what I'm doing for some talkative (but important) mailing lists; you could also do this for addresses you trust to never send you spam. Move them to another Inbox subfolder (they will be kept "unread" and a blue counter will notify you).
If you want to know more about what Outlook rules run on an Exchange server, and what have to be run locally (rules on the server are *always* before SpamBayes), see http://www.slipstick.com/rules/serverbased.htm.
