As far as I know you're correct Karlsson.
As a sidenote - what exactly are you trying to accomplish? Auto-print would be a bad idea in all the scenarios I've been involved with, since most my guests don't carry a printer. Or are you trying to auto-print to ie. a reception area printer?
In that scenario you won't be able to use the client side print anyways, but instead would have to trigger a "remote-print" through some other method.