Como fazer o Ctrl+Alt+Del abrir o System Monitor no GNOME

sudo apt-get install gnome-system-monitor
gconftool-2 -t str --set /apps/metacity/global_keybindings/run_command_9 "Delete"
gconftool-2 -t str --set /apps/metacity/keybinding_commands/command_9 "gnome-system-monitor"