Terminal Services Gateway

I have a Server (2003 SP2, fully patched) at an off site location. I need to be able to use TSWeb to access it. Instead of using a VPN and then using RDP. I have been reading about TS Gateway which is what my question is about. TS Gateway will allow you to tunnel RDP traffic over SSL. My issue is I can not figure out how to install it or rather if it can be used in 2003 Server or if it is just a Longhorn thing. I have browsed around quite a bit in the last few days trying to find info on it but there is very little out there. Any info would be of great assistance. I am really wanting to use this feature versus using something 3rd Party, but any suggestions are welcomed.

Little More info. I have locked down the TSWEB portion using a Verisign Cert. I think that only works for connection. All the traffic I see is still going unencrypted over 3389 when I use RDP Web.