I’m not sure if the AppleScripts used here still work, but you might find it worth investigating this thread:
I realise it is sending stuff in the opposite direction, but there might be something to be learned from using Scripts to set up exchanges.
It seems to me that syncing information between programs, attractive though it is, tends to be fraught with complications, and is often fragile. I’m moving to the idea that it is better to keep one sort of information in one program, and a different sort in another. If you like, I keep source material in DEVONthink or Bookends, and “processed” material in Tinderbox. If I need to go to the source, I use a DEVONthink item link, or a Bookends ID number. I begin to think that having the same information in two places is not a good idea. It eventually gets confusing (to me, at least).