2 original working keys (no copies) are required to self program a third otherwise dealer or someone with suitable software need to program the key.
I believe that my AutoEnginuity program can do it but I have never tried.
I am aware of several people on the US forum that have successfully programed a third key BUT I am not aware of anyone here in OZ that has done it. Sometimes our WH XH don't play like the USA versions.
Here is a link that has instructions
http://www.automotiveandcommerciallo...-instructions/