[O] Remove Org and Tbl from menubar for derived mode

[Christian Wittern]

Hi there,

I am developing a mode derived from org for special editing and browsing 
purposes.  I will add my own menu to the menubar and would like to remove 
the menus added by org, "Org" and "Tbl", in order not to confuse my users, 
who will be Emacs newbies in most cases.
I tried several things like

(define-key org-mode-map [menu-bar Org] nil)
or
(define-key global-map [menu-bar Org] nil)
and some other combinations of this line of thought, but nothing succeeded 
in removing the stuff.

I wonder if anybody here has any advice?

All the best and thanks in advance,

Christian

--
Christian Wittern, Kyoto