But first check if your licence covers this. And if it covers it you would not need to do it like that but could ask KUKA for the installation sources (including necessary windows image). Also there a limitiations on what upgrades are possible depending on the mainboard version (MCC). So talk to KUKA to be sure.
As Fubini wrote, if you are unsure whether your license includes updates, please contact KUKA.
From a technical point of view, if the license is correct (includes update).. in the KUKA_Release folder there is a complete installation of the "new" KSS.