Logout button in gnome?

[Svante Signell <svante signell telia com>]

Where to configure the gnome logout button? 

On one machine running redhat-rawhide and gnome I can either logout from
X, halt or reboot as an ordinary user, just by responding with the
user password. On another machine, running Debian/Potato and gnome the
logout entries does NOT include the halt or reboot options. 

No configuration description has been found so far. The closest I
have got is to the Gnome Control Center, Session Manager/Startup
Programs menu. Which parts of the .gnome tree are affected by making
changes here?

Being able to shut down the computer as an ordinary user is VERY
important if it is to be used as a desktop, since then several users
should be able to start/shut down WITHOUT knowing the root password.

(I'm fully aware of the sudo/super/C-A-Del options available already)

Hoping for help,
svante.signell@telia.com