HFS can display real address of the user in these cases
1) user directly connects to hfs (probably not an option for you)
2) you use NAT on your router. All configuration is to be done on your router, not on HFS
3) you use an http proxy (a generic proxy will hide the address). In this case if the proxy runs on the same computer you need no configuration on HFS. If it runs on another computer you have to configure manually as described at
http://rejetto.com/forum/index.php?topic=6292.0If you are using a generic proxy you have no way to receive external address.
If you are using FRP as proxy, it can be configured as http proxy and/or generic proxy.