8-handed online 20/40: shaky protection

[astroglide]

Preflop: Hero is MP2 with A[img]/images/graemlins/spade.gif[/img], 8[img]/images/graemlins/spade.gif[/img].
<font color="#666666">2 folds</font>, MP1 calls, Hero calls, MP3 calls, <font color="#666666">1 fold</font>, <font color="#CC3333">Button raises</font>, <font color="#CC3333">SB 3-bets</font>, BB calls, MP1 calls, Hero calls, MP3 folds, <font color="#CC3333">Button caps</font>, SB calls, BB calls, MP1 calls, Hero calls.

overlimp is simple for me here, no line on the limper and the table doesn't seem crazy. bb calling the 3bet is enough for me to make a "colorful" call here. i'm not necessarily expecting a cap because it was a button raise.

Flop: (21 SB) 6[img]/images/graemlins/diamond.gif[/img], 4[img]/images/graemlins/spade.gif[/img], 7[img]/images/graemlins/club.gif[/img] <font color="#0000FF">(5 players)</font>
SB checks, BB checks, MP1 checks, <font color="#CC3333">Hero bets</font>, Button calls, <font color="#CC3333">SB raises</font>, BB folds, MP1 folds, <font color="#CC3333">Hero 3-bets</font>, Button folds, <font color="#CC3333">SB caps</font>, Hero calls.

backdoor and gutshot. i'm expecting to call something back to me, but ideally i'd like to get a fold out of somebody with an ace to turn my 4-outer with a backdoor flush into a 6-outer with a backdoor flush. i'm sure queens or kings are out there.