Presumably, you've got port 80 on your router forwarded to your webserver?
Have you got virtual hosting enabled? For example,
www.differentpla.net and
www.beerology.net both resolve to the same address (my router) and the port 80 traffic is forwarded to my webserver (on 192.168.0.4), which uses Apache's virtual host mechanism to work out which web pages to serve up.
Do you want to connect to a different port? Maybe you can configure your router to forward port 81 to the empeg's port 80? Some routers will only allow you to forward a port to the same port number on the internal box, though. To get around this, you'd need to change Hijack to listen on a different port (I don't know if this is configurable).
If you always route port 80 to your webserver, and you're using Apache, you can use
mod_proxy to forward particular virtual hosts (or pieces of your URI namespace) to another webserver (i.e. the empeg). I don't know if there's an equivalent setting in IIS.