When to fold a set...

[erc007]

Party Poker No-Limit Hold'em, $ BB (10 handed) converter

UTG+1 ($29.50)
UTG+2 ($36.40)
MP1 ($58.95)
MP2 ($52.65)
Hero ($57.10)
CO ($48.50)
Button ($11.50)
SB ($28.45)
BB ($45.80)
UTG ($84.63)

UTG+2 is 20/5/1 after 75 hands. He hasn't done anything notable before this hand.

Preflop: Hero is MP3 with 6[img]/images/graemlins/spade.gif[/img], 6[img]/images/graemlins/club.gif[/img]. SB posts a blind of $0.25.
<font color="#666666">2 folds</font>, <font color="#CC3333">UTG+2 raises to $2</font>, <font color="#666666">2 folds</font>, Hero calls $2, CO calls $2, <font color="#666666">2 folds</font>, BB calls $1.50.

Flop: ($8.25) 5[img]/images/graemlins/club.gif[/img], K[img]/images/graemlins/heart.gif[/img], 6[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(4 players)</font>
BB checks, UTG+2 checks, <font color="#CC3333">Hero bets $4</font>, CO folds, BB folds, <font color="#CC3333">UTG+2 raises to $10</font>, Hero calls $6.
At this point I put him on 3 hands: AK; AA; and KK...so I'm either WA/WB. I was kinda leaning towards AK, b/c he can have that hand 4 ways, plus the fact that a lot of these guys like to limp AA.

Turn: ($28.25) 4[img]/images/graemlins/diamond.gif[/img] <font color="#0000FF">(2 players)</font>
UTG+2 calls $24.40 (All-In), Hero calls $24.40.
This action didn't change my read, and getting 2 to 1 from the pot, my set only has to be good 33% of the time to break even (correct me if I'm wrong.) I've also seen a lot of guys push with top pair. This said, my question is how sure (in terms of a percenatge of certainty) would I have to be to correctly lay down my set?

River: ($77.05) Q[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players, 1 all-in)</font>

Final Pot: $77.05