[away3d] Tweener.addTween(Primitive, {position:Number3D, time:2}) don't work?

[metSyS]

Why i can't change position of some primitive in this way :

public var pos:Number3D=new Number3D(-33, -36, 0);
public var c:Cube=new Cube();
...
Tweener.addTween(c, {position:Number3D, time:2});