Sorry, I don't know the difference. Is this the topology?
You behind ISA 2004 -> Internet -> Connect to Connectra behind some kind of firewall -> connect to internal HTTP server -> redirect to HTTPS server
However if you installed ISA 2004 SP2, make sure you also installed the post-SP2 hotfix or you will have other headaches:
http://support.microsoft.com/kb/916106/en-us Are you traversing ISA 2004 as a SecureNAT client, a firewall client and/or a web proxy client?
Ray