♠ shortness can probably be shown lower (3♠ instead of 4♣) ;) The exact sequence was (opps quite): 1NT-2NT-3♣-3♠-3NT. 3♠ was "short spades, place the contract in 3NT o 5♦". I had two problems: first was to stayman or to show the long diamonds. Second was to treat it as an invitation in diamonds or a FG hand (in case my p didn't superaccept). My p had downgraded a 4=3=3=3 17 count with AJx in ♦ to 1NT, so was happy to accept any invitation.