How often should I 3bet this flop?...stars 400nl

[James00]

Villain is gaussie, dont know much about him. So I guess I would be readless but my intial impression is that he is semi decent.

PokerStars No-Limit Hold'em, $4 BB (6 handed) internettexasholdem.com

SB ($372.80)
BB ($556.45)
Hero ($479.75)
MP ($645.20)
CO ($388)
Button ($254.40)

Preflop: Hero is UTG with A[img]/images/graemlins/club.gif[/img], A[img]/images/graemlins/heart.gif[/img].
<font color="#CC3333">Hero raises to $12</font>, MP calls $12, <font color="#666666">4 folds</font>.

Flop: ($30) 6[img]/images/graemlins/diamond.gif[/img], K[img]/images/graemlins/club.gif[/img], 8[img]/images/graemlins/heart.gif[/img] <font color="#0000FF">(2 players)</font>
<font color="#CC3333">Hero bets $22</font>, <font color="#CC3333">MP raises to $52</font>, Hero ...

So theres no history and reason for me to believe he would look me up super light.