...they say only Tool Bar menu can be custamized with options whateve IW has provided in the FormPublisher document.
This used to be the case in previous versions, but in 6.7.2 you can add 'custom plugins'. Have you looked at the "TeamSite Suppliment" document for 6.7.2 (page 77)? We're currently working on some customisations and have added some successfully, but they're all just buttons, so I'm not sure about a custom drop-down.