I have stock ROM 4.1.2 with XXMS2 and didn't found this in the list.
I wasn't sure which one to install because I only found XXMS1 but it's not the same I think.
I was afraid that I'm going to do something wrong...
This is a really good and detailed method but I didn't want to install any custom recovery yet.
Thank you for both of you but I found the easiest way in this topic: http://forum.xda-developers.com/gala...4-1-2-t2116549
I flashed the superSU from stock recovery and everything went just fine. This root can be applied to any 4.1.2 stock fw.
But I really appreciate all your help!