Adding an entry to the menu bar

[Tim Allen]

Hi

I'm trying to add an entry to the Buffers menu bar (for creating a new
scratch). My attempt below works OK when adding to the Files menu, but
changing "files" to "buffers" does not insert the new menu option:

(define-key global-map
  [menu-bar files create-scratch]
  '("New buffer" . create-scratch-buffer))


I think this may be because the contents of the Buffers menu is created 
"on-the-fly", as it needs to list the actual buffers present. Can anyone 
help with this?

Thanks  

Tim