The ISA Server 2006 Supportability Update is more than only another patch for the ISA Server; it is a combination of fixes and improvements for the product. I worked on a couple of cases where customer would like to install the ISA Server 2006 with this update built in, what we call slipstream version. However Microsoft doesn’t have a slipstream version of ISA Server 2006 with SU on it, but it is easy to do that on your server. Here how to do it:
1) Copy all the ISA Server files from the CD to a folder on your server (for example: C:\ISABin)
2) Download the Supportability Update to the same folder.
3) Open the command prompt, go to the C:\ISA\FPC folder and run the command below:
msiexec /a MS_FPC_Server.msi /p ISA2006-KB939455-X86-ENU.msp
4) Install ISA Server from the path C:\ISABin\ISAAutorun.exe
Happy ISA Server installation for you J