Applescript to change Page setup in PowerPoint for Mac

Question

Very new to AppleScript.    I'd like to change the Page Setup to "On-screen show (16:9)".  Within PowerPoint it is under File>Page Setup>Size>Slides sized for : On-screen Show (16:9).    I did find within AppleScript that the Slide Size is a Property of the Page Setup Class within the Microsoft PowerPoint Suite.  It is also listed under the Application Class >Command Bar Class>Command Bar Control.  The Page Setup inherits it's properties from Base Object.
I tried to manually record the process of opening a PPT file and choosing File>Page Setup>Size>On-screen show (16:9) but it only recorded the process to activate PPT and open the file.
I wrote this script:
tell application "Microsoft PowerPoint"
     activate
     open {file"MacBook Pro Hard Drive:Users:Patrick:Desktop:AppScript.pptx"}
set slide size to "on-screen show"
end
I get the error "Syntax Error :  A property can't go after this identifier" and "slide size" is highlighted.
I'm stuck......Slide Size is a property of the Page Setup Class.  How should I write this ?
Script Editor V. 2.7(176) and PowerPoint for Mac 2011

Answer 1

http://answers.microsoft.com/en-us/mac/forum/macpowerpoint?tm=1366105550521.
That's where the PowerPoint experts hang out...
Clinton