Excellent work. Or.......use a 2008 server and enable the RD Gateway (by default) and you're done. You don't have to open the dreaded port 3389 and you get remote into any computer on the network using the FQDN.
Now you will have to forward port 3389 to port 3390 for the next computer and so on. Best to change port 3389 to a different port for security.
But, following Sandeep's guide will definitely get you set up. But, after awhile, like a month or less, I would have the router listen on a different port.
Again, incredible guide.
I'm interested.