If you open the Tabbed Dock configuration you should see an option on the left hand side called Tabs and Styles. If you click that it should take you to a window where you can add tabs.
Now the bad news, I believe that I have read that you can't get the System Tray to work in Vista 64 bit.
Thanks! Definately wasn't obvious to me.
I've added the tab, and it's empty, but I'm going to wait for a reboot before I declare it busted.
Thanks again!