In order to make Thinfinity® Remote Desktop Workstation available from the internet, all you need to do is to check the 'Use UPnP option' present on the Communications tab.
Configuring the router:
Once you have enabled the UPnP option, the application will try to automatically open the port for you on the router. If this doesn't work, you can manually forward the external port to your computer's Thinfinity® VNC listening port.
Test the access:
Test the internet access from a outside machine, by typing into a browser the following url: