Welcome to the MPV forums!
I'm not near DVDStudio Pro right now... have you tied right-clicking on the tool bar and choosing 'customise toolbar?'
I can't remember if DVDStudioPro support this feature available in other Apple Pro Apps.
Let me know how you get on.
FCP tool pallet is set, it can't be customized. All tools in FCP are there already. What tolls did you want to add? Perhaps look up Button Bars in the user manual, that may be an option that works for you.