Interface Builder now lets you create NSToolbar. If this is in a Window you can set the default items by dragging to the toolbar.
If it is a different NIB this does not seem to be possible.
I have a NSToolbar in a NIB which contains a View and its controller (so that it is easy to connect to the action methods). There seems to be no way to view the toolbar, and thus set the defaults.
I do not want this toolbar to be customisable, but need to set the contents.