Cannot set key sequence to kill the X server using gconftool-2

[Lenin]

Binary package hint: gconf2

Require gconftool-2 command that will do the same as the following in gnome-keyboard-properties:
1) Go to System> Preferences> Keyboard
2) Select Layout> Layout Options
3) Expand the option Key sequence to kill the X server and enable the Control + Alt + Backspace

Unfortunately I have not been able to come up with a working command for this. I believe this to be a bug since the gconf key is entered properly when entered automatically by gnome-keyboard-properties.

The buggy command is the following (tested in 10.04 and 10.10):
$ gconftool-2 --type list --list-type string --set /desktop/gnome/peripherals/keyboard/kbd/options '[lv3 lv3:ralt_switch,terminate terminate:ctrl_alt_bksp]'

It seems that the bug has to do with an invisible character between the two words "terminate" which seems to me like a tab.