still menuitem lock when lock-enable = false

I have a custom.gschema.override for my system:
...
[org.gnome.desktop.lockdown]
disable-lock-screen = true
disable-user-switching = true
disable-print-setup = true
user-administration-disabled = true

[org.gnome.desktop.screensaver]
lock-enabled = false
ubuntu-lock-on-suspend = false
user-switch-enabled = false
idle-activation-enabled = false
...
so this works for 12.04 to disable menuitem lock screen but not for 14.04 yet.
The menuitem have no function (goes to black screen and after mouse motion it goes back to desktop)
but how can I remove the menuitem? Thanks for help.