Non-standard SSL ports
By default, ISA 2000 is set to only allow port 443 out via the Web Proxy service for SSL connections. If a non-standard port is needed, like 9443, then you have to run the following script. Edit the port number in all 3 place and then save it as a VBS file and run at the ISA server.
NOTE: you must stop start ISA servies aftewards. Just WebProxy, but FW can't hurt.
set isa=CreateObject("FPC.Root")
set tprange=isa.Arrays.GetContainingArray.ArrayPolicy.WebProxy.TunnelPortRanges
set tmp=tprange.AddRange("SSL 9443", 9443, 9443)
tprange.Save
Reference Article: http://support.microsoft.com/kb/283284