Sorry for such a late response. I have been in the new OmniFocus forum for OF2.
I am not sure if you are wanting a linked file or an embedded file.
I would suggest taking the script from Rob Trew in post
26 of this thread and modifying that script. You should be able to verify the current script variables are correct for you situation and add in the requirement in placing a task into a specific folder. I hope this helps.
You should also know the AppleScript library for OF2 has been changed and this can effect current scripts. I have not tested any scripts in OF2 and will probably not do so until it is officially released and determined if I am going to upgrade to the new version, continue using OF1, or moving to another solution.