Anchor at connectedbody

How can I get the anchor of a Hingejoint at the position of the connectedbody?

I have 2 cubes. The red ones can move and the blue one only follows. The blue one has an HingeJoint and the connectedbody of the hingejoint is the red cube.

How can I make sure that the anchor of the connectedbody stay at the same position as the red cube?

function Update(){

	verticaal = Input.GetAxis(script.verticaal);

 	if (Mathf.Abs(verticaal)<0.5) 
 	{
 		verticaal = 0;
 	}

		if(verticaal != 0)
		{

			transform.hingeJoint.connectedBody = null;

			if(transform.position.y > 2 && verticaal < 0.5 ||transform.position.y < 23 && verticaal > -0.5)

			{

				transform.position += Vector3.up*verticaal;

				transform.hingeJoint.connectedBody = redcube.rigidbody; 

				transform.hingeJoint.anchor.y = redcube.transform.localPosition.y - bluecube.transform.localPosition.y;

				transform.hingeJoint.anchor.x = redcube.transform.localPosition.x - bluecube.transform.localPosition.x;

			}
		}
}

I used a Configurable joint and added the joint at the other cube.
More information can be found: http://forum.unity3d.com/threads/41147-Moving-hinge-joint-in-a-script-has-no-effect