There's a kb article out there that appears to be providing incorrect information as to how to allow Lacerte to work with ISA. It's KB 839503. In fairness it is written for ISA 2000, but even when translated into ISA 2004 lanuage it still appears incorrect. Jim Barr found a rule that works. Here's how to create it.
1. Click Create New Access Rule, call it Lacerte Outbound and make it an Allow rule.
2. Apply the rule to All Outbound traffic.
3. Traffic will be from the Internal Network Set.
4. The rule applies to traffic to these two Address Sets: 188.8.131.52-140 and 184.108.40.206.
5. This rules applies to all users.
Click on Apply to let the rule take effect.