Our recommended way for tomcat traffic reports is to implement "bug" 1x1 pixel image into your site and track visitors based on this "bug".
This site Urchin/Google is using simular method (there are many other sites/software) that offer the same tracking method. Please check this out so you can fully understand what we mean:
http://www.google.com/analytics
The main reason we recommend above mention mechanism is due to tomcat logs format/logging facilities and most importainly because we do port redirection before request is forwaded to tomcat.
