“Internal Commands” and “Internal Objects” don’t actually need to be enabled in Catalog>Quicksilver for Merlin’s tip to work. In fact, “Proxy Objects” is only necessary if you want to dynamically address whatever application is frontmost. If you want, you can access menus directly in an application individually by placing it in the Noun portion of the QS interface and then choosing “Show Menu Items” as the Verb.
Though I suppose the first pane in Quicksilver should probably be called the Subject, as the dynamically-appearing third field is a “noun” as well but could more accurately be described as an Object.