The ISA server team has posted a guide on the subject (in three parts). The guide covers most aspects of the subject including troubleshooting. Part 1 Part 2 Part 3
With the release of ISABPAV5 comes a new and neat tool (in my opinion) called BPA2VISIO. It's goal can be perceived from its name, it will use the information gathered by the BPA and based on that information it will create a drawing of how ISA sees...