How to set default page setup to A4 systemwide

Try this

--script begins

on run

do shell script "defaults write com.apple.print.PrintingPrefs DefaultPaperID 'iso-a4'"

end run

--script ends

I assume you know how to set it up to run at login.

Sori Heimsson wrote:

My problem is however that it does not work in combination with this solution:

http://support.apple.com/kb/HT2420?viewlocale=en_US

on how to make it run at login for all users.

(1) A login hook requires a shell script, not an AppleScript.

(2) I believe that login hook has been deprecated in SL (the KB item you quoted applies to 10.5 and lower).

(3) Save the script as an app and implement it as a LaunchAgent (as described in "Creating Launch Daemons and Agents" in "Daemons and Services Programming Guide" in Apple's Developer library). Save the .plist in </Library/LaunchAgents> and it will apply to all users. It's the preferred method in SL, and, IMHO, superior to the login hook.

HTH