TMG 2010 Port Forwarding HTTPS Traffic

Hi,

I need to forward all HTTPS traffic that hit one of my TMG external public IP addresses (20.100.123.100) to an internal HTTPS server (10.0.0.100).
The internal https server runs multiple customer websites and I have no control over their domain names and SSL certificates so creating a SSL web publishing rule will not help here. 

I created a non-web server publishing rule but the TMG denies the traffic as its destined for the localhost (20.100.123.100) and doesn't forward it on to my internal https server.

Is their a way to simply forward all https traffic from 20.100.123.100 to my internal https server 10.0.0.100? 

If so what rule would I need?

Thanks,

Microsoft Partner