Sniffer Custom Rules and Spam Submission
One of the advantanges of using an active MessageSniffer subscription together with MxScan is the ability to submit sample spam messages that are making it past all of the existing filters and have those new rules automatically downloaded on your next rule update.
For more information on Spam Submission for Sniffer please see http://www.armresearch.com/support/articles/procedures/spamSubmissions.jsp
And for any special needs that require special rules for the rulebase (such as blocking on some "bad words" or blocking character sets or other structures) you should send an ordinary email to email@example.com to request the special rules. They will work with to make any changes needed in the rulebase.