Looks like the function is disabled in netbeans 6.
Issue 94193: Not possible to edit bean properties in the Outline window or through source packages in the Projects window.
Description: In NetBeans
IDE 6.0, the Add Menu item is disabled in the Navigator window and there is no functionality for editing the properties through source packages.
http://www.netbeans.org/community/releases/60/relnotes.html