Anti Spam Protection Does Anyone Know How To Configure The Heuristic Option In Symantec Premium Anti Spam?

Does anyone know how to configure the heuristic option in Symantec Premium Anti Spam? - anti spam protection

I have set out from Symantec Premium Anti-Spam on a SBS box with Exchange. The heuristic option is gray. There is no way, individual strategies for creating good. The manuals are good but a little short of answering questions. This is version 5 as an additional premium groupware. License is active and has 344 days time, but only the default settings can be changed. Settings spam detection is set to 25, but still a lot of spam, it goes through. I use some vendors default RBL Blacklist Whitelist /. When I figure out how to activate the heuristic level, which can attain a degree of control.