In this article Greg Sheilds will show you how to configure a Remote Desktop Gateway which you can place behind your TMG firewall in order to provide for secure remote access to RDP clients on your corporate network. Note that you’ll need to registrer for a free account in order to read this article, which is part of a two part series.
http://searchwindowsserver.techtarget.com/tip/Bringing-Windows-RDS-to-the-web-Designing-the-DMZ