Why is it so hard to book a codeshare seat
Codeshare flight DL 8604 CDG to BOS. In the back. I can't confirm a seat

I have a seat on DL.com, but have read this is useless. I have the booking # and can log into KLM.com and AF.us and see my reservation but no seat assignment! When I pick a seat on KLM.com it says the seat is not available. When I use AF it says can't do it due to tech issues. Also, the seats available on DL/AF/KLM are all different..
Any ideas?
Last edited by RSSrsvp; Jan 26, 2011 at 3:17 pm
Reason: Merged with the original thread on this subject. No need for a dupe thread.