HI
you don't need Enterprise for reverse proxy. Check
http://www.wingate.com/products/wingate/licensing.php for details between types of licence.
There are several ways you can grant access to an intranet server. depending on what you want to do, and what you want the intranet server to see.
1. use port security setting to map a port. This has the advantage that the intranet web server can still see what IP connects to it.
2. use a TCP mapping proxy. This is simpler than using the HTTP proxy, but allows less control.
3. use the WWW proxy - under "websites", configure which hosts you wish to reverse proxy for. This allows you multiple reverse proxying, plus policy control over the requests made.
Regards
Adrien