Applescripting file attachments

[James Spahr]

Is it possible to do? This is what I'm trying:

--

set f to alias "MacHD:Users:james:foo:bar.pdf"

tell application "OmniOutliner"
	set the_current_row to selected row 1 of document 1
	set new_row to make new row at the end of (children of the_current_row)
	make new text attachment at end of topic of new_row with properties 
{file name:f}
end tell

--

I get an error when I try to make the attachment. I also tried the 
'add' command without any luck.