We apologize for the confusion.
DKS is seen as a new game because it's a separate disc and a new Title ID. If we would have been able to release FoV as a DLC, then you would have been able to continue.
And as Raze indicated, even if the Title ID would somehow be the same, DKS saves are not compatible with ED/FOV saves due to major changes.
Again, we are sorry if this was not clear.
The topic was discussed several times on the forum:
Example:
http://www.larian.com/forums/ubbthreads.php?ubb=showflat&Number=421196&fpart=1
