Non-standard SSL ports
By default, ISA 2004 is set to only allow port 443 out via the Web Proxy service for SSL connections. If a non-standard port is needed, like 10000, 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.
Dim root
Dim tpRanges
Dim newRange
Set root = CreateObject("FPC.Root")
Set tpRanges = root.GetContainingArray.ArrayPolicy.WebProxy.TunnelPortRanges
set newRange = tpRanges.AddRange("SSL 10000", 10000, 10000)
tpRanges.Save
Reference Article: http://support.microsoft.com/kb/283284