That's a pretty old version of Beyond TV. You should probably just download Beyond TV 4 from the website to make sure you have the latest version.
If you switch to Beyond TV 4, you will see the option in the Setup Wizard.
Either way, you can use the web admin. The web admin is an advanced interface that allows you to configure settings that are not exposed in the main application. Simply open a web browser on the computer that you have Beyond TV running and navigate to
http://localhost:8129.
Here is a KB article that details the process:
http://snapstream.helpserve.com/inde...articleid=1169