Nut flush on paired river vs Call Station

[TheRempel]

Villain in this hand is awful and can be overcalling pretty wide and would not likely reraise a set on the flop. He got his stack like 3 hands previous by check calling three streets with a King high flush draw when I had top set and the bare ace. I am about 70% sure he has a flush. Do I bet? How much and why? (He has $360ish behind and the pot is $766)

Full Tilt Poker
Pot Limit Omaha Ring game
Blinds: $2/$4
6 players
Converter

Stack sizes:
UTG: $669.70
TheRempel: $944.85
CO: $706.10
Button: $33
SB: $266.20
BB: $139

Pre-flop: (6 players) TheRempel is UTG+1 with 9[img]/images/graemlins/diamond.gif[/img] 6[img]/images/graemlins/heart.gif[/img] 7[img]/images/graemlins/heart.gif[/img] A[img]/images/graemlins/heart.gif[/img]
<font color="#cc0000">UTG raises to $9</font>, TheRempel calls, 2 folds, SB calls, BB folds.

Flop: ($31) 4[img]/images/graemlins/heart.gif[/img] 3[img]/images/graemlins/heart.gif[/img] K[img]/images/graemlins/club.gif[/img] (3 players)
SB checks, UTG checks, <font color="#cc0000">TheRempel bets $22</font>, <font color="#cc0000">SB raises to $97</font>, UTG calls, TheRempel calls.

Turn: ($322) J[img]/images/graemlins/heart.gif[/img] (3 players)
SB checks, UTG checks, <font color="#cc0000">TheRempel bets $222</font>, SB folds, UTG calls.

River: ($766) 3[img]/images/graemlins/club.gif[/img] (2 players)
UTG checks, TheRempel ?