Proper yoke calibration

Dear flight sim enthusiasts!

I just bought a brand new CH yoke with rudder pedals few days ago.
It's well done (for the price) and adds a new dimension to the game.

However the big problem with the yoke is that i can't calibrate it
properly. The result is that i'm fighting all the time with the
aircraft to correct the severe left turn tendency. It's not because of
the p-factor or torque effect, i tested it using a joystick and the
keyboard.

Under WinXP Pro with the default drivers, i did use the calibration
tool but still, the left turn tendency is still there. Is there any
better calibration tool or any tricks to fix this problem?

Thank you!
Matt