Calling a raise with AKo

[artman]

Sít n' Go at Absolute poker. BB is $40 and i'm UTG with AKo. I decide to limp, 3 other people limp with me and then the SB raises to $80. Everyone calls. SB is the biggest stack with about $3500. I have about $1400. Starting stacksize is $1500.
The flop:23A rainbow
SB bets $360 and i call. All others fold.
Turn:7
SB checks and now i move allin. SB thinks for a while and calls. How did i play this hand? And what do you think the SB had? [img]/images/graemlins/confused.gif[/img]