rotation x changes all angles?

I tried to change just the x rotation of an object(the head shoult look in the direction, that the camera has) but the y and z angels are also influenced and I dont't know why. Any solutions?

var Arm : Transform;

var Head : Transform; var Kamera : Transform; var Charakter : Transform;

function LateUpdate () { //This here works correct Arm.rotation=Kamera.rotation;

//this here doesn't work :/
Head.rotation.x=Kamera.rotation.x;

}

Transform.rotation uses Quaternions.

Use Transform.Rotate instead and set the angles for y and z to zero.

Unity stores rotations as Quaternions internally. To rotate an object, use Transform.Rotate. Use Transform.eulerAngles for setting the rotation as euler angles.

http://unity3d.com/support/documentation/ScriptReference/Transform-rotation.html

Transform.rotation is a quaternion, and you generally don't want to modify its elements directly.

Try Transform.eulerAngles instead.