How to set papersize?

Hi all,
Since my default paper is not A4,
I use printer.papersize=9 to set my printer to A4 paper.
but nothing is happen!

I also wanna change my default printer as following code:
set printer=printers(2)
but nothing is happen again!

Who can tell me why and how to fix it, Thanks!

Hi! You must end this document before returning to using the Printer object

Code:

---

      Printer.PaperSize = 8
      Printer.Print "Testing 8"
      Printer.NewPage
      Printer.PaperBin = 9
      Printer.Print "Testing 9"
      Printer.EndDoc

---