Well, as far as I'm concerned, I don't need to rewrite the whole menu
entry, I just need to change the section="" field. E.g:
ardour-gtk: "Apps/Sound" -> "Sound/Recorders/Multitrack"
Thus the idea is that I only customise the section/menu-path with:
Pkg-Menu-Path: Sound/Recorders/Multitrack
Depends: ardour-gtk
and then I have a script in /etc/menu (or whatever location), which
can be common for all CDDs, and that is invoked by update-menus and
write on standard out a menu entry identical to the original one that
comes with the ardour-gtk package, but with the my custom menu path.