Just to show you how well trained DL agents are, I just called them to check for availability on SU for a VVO-PKC award because they don't show it on the DL site. The first agent I spoke with checked with a supervisor and said that even though I'm using DL miles to book the award, I have to call SU to book it (if that makes sense!).
I called back and a 2nd agent said that even though SU is part of SkyTeam, you can't use DL miles on them. She even stated "I'm positive" when I asked her if she was sure about that. When I asked her how come I knew someone who was able to book an award ticket on SU using DL miles (I don't but I wanted to hear her reaction), she put me on hold to check with someone else and then came back and apologized saying that you could indeed do it. Then, she checked for availability and although she was able to find it, she said that for some unknown reason to her, she couldn't price it and therefore couldn't book it or tell me how many miles it would cost me.
I guess I have to call a 3rd time to see if they can really help me next time.