Applescript to use to select the new task that is created by a script

Am using @curt 's Complate-and-Await-Reply script. Thank you for the script.

Now I would like to select the new task that is created (Assuming only one task is mark completed) in the process.

This line in the below code “set selected of theDupe to true” does not seem to do the job.

tell application "OmniFocus"
 tell front document
	tell content of document window 1
		set theSelectedItems to value of every selected tree
		repeat with anItem in theSelectedItems
			set theDupe to duplicate anItem to after anItem
			# selecting the new item
			set selected of theDupe to true
		end repeat
	end tell
  end tell
end tell

Any advise as to how to select the new item? Thank you.

Trying to select that item as I would like to reuse another script that allows me to set start, due and estimated_duration of a selected task.