No you are right, this is NOT a kix problem. I just thought that there might be a work around.
The problem is that Xerox drivers for our site didn't work, in fact they were incredibly unstable. The copiers are quite old and Xerox have no intention of fixing the issue properly. They however issued a few patch drivers that were not digitally signed. The group policy changes mentioned above work well for digitally signed drivers but prompt users if they aren't digitally signed.

I just thought there might be a way from a kix script to run the addprinter command with admin rights so that the end user get the printer installed.