Question : HTTPS traffice doesn't pass through from one of the internal networks.

My network configuratoin is 3 internals networks, connected to ISA server 2006 (4 network cards in total). I need to be able to activate windows xp machines from all of my internal nettworks. During activation, WindowsXP is connecting to http://wpa.one.microsoft.com and then to https://wpa.one.microsoft.com. From my Internal Network #1 everything works fine. Activation doesn't work from my other 2 internal networks despite the fact that for test purposes I configures exactly the same all my 3 internal networks.
If I try the following command "telnet wpa.one.microsoft.com 443" from my Internal Network #1 - it works. From my other 2 internal networks I'm getting "Connection Failure" error.
My routing table on ISA machine seems fine. I have only one defaoult route through my ecxxternal interface.
I've seen "HTTPS access through ISA 2006" article, but I didn't understand how to adjust HTTP timeout settings and if that setting allpies globally, then it's not my case since I have it working fine from one of my network.

Thank you.
Any help is greatly appreciated.

Answer : HTTPS traffice doesn't pass through from one of the internal networks.

Can you supply both an ipconfig /all and a route print please from the ISA?

Does the Cisco have a static route applied so it knows how to get back to ALL of your internal networks ie the ones on the other side of the ISA external nic?