[Joel]

Here's the full Script instead of just a snippet:

tell application "OmniGraffle Professional 5"
	tell canvas of front window
		make new shape at end of graphics with properties {draws shadow: false, size: {68.000000, 60.000000}, origin: {152.000000, 112.000000}, stroke join: miter}
		set jump of graphic -1 of it to canvas id 2 of document of front window of application "OmniGraffle Professional 5"
	end tell
end tell