[bongoman]

Thanks for that whpalmer.

That script is way more complex than I needed but I was able to extract the relevant bits into this:

on handle_string(action)
	try
		tell application "OmniOutliner Professional"
			set theDocument to the front document
			make new row at end of theDocument
			indent the last row of theDocument
			set topic of last row of theDocument to action as international text
			save theDocument
		end tell
	end try
end handle_string

It could be improved, I know, but it's working.