Controlling the rotation of brushless motor by changing polarity

Hi, Guys.
I have a brushless motor like this one.

  • BLDC motor : 12V, 7W, 1A, 2400rpm, Torque 0.25kgf-cm, built in driver
    Although this motor is three phased, it has only two wires which is + and -.
    Clock wise rotation is good. But, I want this motor to be rotated in counter clock wise as well.
    How can I acheive this?
    Specifically, I want to control the rotation by changing the polarity of DC12V to this motor.
    This motor's pictures are shown through this link.
    mingkimingkimingki | Flickr

This is a duplicate post, please go here: Controlling the rotation of brushless motor by changing polarity - General Electronics - Arduino Forum

(Please please don't cross-post, it wastes everyone's time and caused confusion)

I am sorry, I didn't mean to do that.
I was so desperate to get help. Please understand.
Thank you.