All Disney Resort Guests (including DVC Resort Guests) can begin to book dining reservations beginning at 180 days from arrival. At that time, they can make dining reservations for up to the first 10 days of their stay.
You would need to link your DVC Reservation to your disneyworld.com account, BUT the issue most DVC members are encountering is that the on-line dining reservation system is not allowing them to make dining reservations past the 180 day mark. If you are looking for a hard to get ADR, your best bet is to call at 180 days to book the ADR.
Yes I've done it. As above poster said, just link your resort confirmation number and it shouldn't be a problem. If the website gives you trouble, since it's still in it's changing over phase, just call and they will do it for you.