Let's be clear. It doesn't matter how many different ways you try asking this same basic question, the answer is always going to be the same: It is not possible.
It doesn't matter if you're trying to use the Registry, VBScript or whatever other method you might think of next. What you want to do is simply not possible. You need to stop wasting time chasing an impossible dream and start looking at other ways of approaching this problem. Short of getting Microsoft to give you a copy of the Windows source code so you could make your own custom print dialog box, and then having to maintain that custom dialog box in perpetuity, there is no way to alter it.
I would strongly suggest you stop wasting time trying to solve an impossible problem.