South has: Ax Xxxx Jxxxx Xx Bidding goes (West deals, NS pass): 2NT-3H 3Sp-4C 4NT-5D 6Sp South asks after the meaning of 5D and is told by West that it shows 1 or 4 keycards with spades as trump. Before the opening lead East corrects this to 0 or 3 keycards. South now says he wants to double. As it happens, North has Kx of spades... How do you deal with this?