Endymion77, on 2013-August-19, 04:06, said:
3♣ would be a forcing club raise here, so 4♣ would be a splinter and your next bid. Bid your hand and see if your partner cooperates with a red ace cuebid. Then you suggest a sign off in 4♠ and see if he would like to go on (♠Kxx ♥Ax ♦xxx ♣Axxxx is enough for slam but you really would like no club wastage).
On reflection, I agree entirely with the above comment. I had thought of continuing with RKCB after a red ace cuebid, but this is dangerous and unnecessary - partner will proceed further over 4S if he has three key cards.