Alberto, please see screenshot (https://bugs.launchpad.net/ubuntu-gnome/+bug/1245188/+attachment/3892954/+files/Keyboard%20Layout%20Options%20-%20LEDs.png) from Ubuntu 12.04.3. It was under gnome-control-center-keyboard (see bug 1245064). What version(s) of Ubuntu do you have installed, Alberto?
Alberto, please see screenshot (https:/ /bugs.launchpad .net/ubuntu- gnome/+ bug/1245188/ +attachment/ 3892954/ +files/ Keyboard% 20Layout% 20Options% 20-%20LEDs. png) from Ubuntu 12.04.3. It was under gnome-control- center- keyboard (see bug 1245064).
What version(s) of Ubuntu do you have installed, Alberto?