As a heads up … if you are installing SBS 2003 Premium with Windows Server SP2, your ISA 2004 installation may go belly-up. Steven Teiger just encountered such a situation: CEICW failed, and then upon restarting the SBS server, all of the ISA services failed.
According to Eriq Neale, you need to do the following steps:
1. Install SBS with SP2 (do basic setup, without ISA)
2. Disable ALL scalabale networking pieces. (Read Eriq’s detail step-by-step instructions here)
3. Download ISA 2004 SP3, then install ISA 2004 followed by installing ISA 2004 SP3.
In fact, if you were to run the SBS BPA after step 1, it also identifies the scalable networking pieces to be changed.
Hope this helps!