Thread:Project:Support desk/How do I add a third namespace tab?

How do I make a third namespace tab, such as the one in this example? http://en.wiktionary.org/wiki/Gretel I'm planning to a peer reviewed wiki at some point where the main article is only editable by authorized users, but any users can edit a draft namespace of the article and the talk page for it. I want the tabs for all three pages of the article to appear on each of them.