Setting QuickTime preferences to long delay

I am trying to automate the Streaming Speed from short delay to long delay in QuickTime Preferences but I have no idea on how to accomplish this. I have the following applescript. Any help would be appreciated.

Thank you,

Schoop

tell application “System Preferences” to activate
tell application “System Events”
tell process “System Preferences”
delay 2
click menu item “QuickTime” of menu “View” of menu bar 1
delay 2

end tell

end tell