IIS reverse proxy
You can do i with the modules URL Rewriting and Application Request Routing.
http://www.iis.net/learn/extensions/url-rewrite-module/reverse-proxy-with-url-rewrite-v2-and-application-request-routing
If you only have one backend server route traffic straight to it and just use URL rewriting to port redirect traffic locally.
edit: or use HTTP redirection which might be the best alternative.
http://technet.microsoft.com/en-us/library/cc732930(v=ws.10).aspx
http://www.thomasmaurer.ch/2010/11/how-to-redirect-sites-to-https-in-iis-7-5/