[away3d] Tween TargetCamera3D

[metSyS]

How to make a tween changing of camera target?

Here's a me code :
package {
        import away3d.cameras.TargetCamera3D;
        import away3d.containers.ObjectContainer3D;
        import away3d.containers.Scene3D;
        import away3d.containers.View3D;
        import away3d.core.base.Object3D;
        import away3d.core.render.Renderer;
        import away3d.events.MouseEvent3D;
        import away3d.primitives.Cube;

        import com.as3dmod.ModifierStack;
        import com.as3dmod.modifiers.Bend;

        import flash.display.Sprite;
        import flash.events.Event;
        import flash.text.TextField;

        [SWF(width="1024", height="768", frameRate="30",
backgroundColor="0xFFFFFF", quality="high")]
        public class Primitive extends Sprite
        {
                private var scene:Scene3D;
                private var view:View3D;
                private var cam:TargetCamera3D;

                private var pGroup:ObjectContainer3D;
                private var p:Cube;
                private var p2:Cube;

                private var mStack:ModifierStack;
                private var bend:Bend;

                private var txt:TextField=new TextField();

                public function Primitive()
                {
                        init();
                        //addObjects();
                }

                private function init():void
                {
                        scene=new Scene3D();

                        cam=new TargetCamera3D();
                        cam.z=-800;
                        cam.x=200;
                        view=new View3D({scene:scene, camera:cam, 
x:(stage.stageWidth/2), y:
(stage.stageHeight/2)});
                        view.renderer = Renderer.CORRECT_Z_ORDER;

                        addChild(view);

                        pGroup=new ObjectContainer3D();

                        p=new Cube({width:100, height:100, depth:100, x:100, 
rotationX:-90,
rotationZ:180, segmentsW:5, segmentsH:5});
                        pGroup.addChild(p);

                        p2=new Cube({width:100, height:100, depth:100, x:-100,
rotationX:-90, rotationZ:180, segmentsW:5, segmentsH:5});
                        pGroup.addChild(p2);

                        view.scene.addChild(pGroup);
                        pGroup.addOnMouseDown(mouseDownP);

                        /*mStack=new ModifierStack(new LibraryAway3d(), p);
                        bend=new Bend(0.1, 0.5);
                        mStack.addModifier(bend);
                        mStack.apply();*/

                        addEventListener(Event.ENTER_FRAME, onEnterFrame);
                }

                private function mouseDownP(e:MouseEvent3D):void
                {
                        var object:Object3D=e.object;
                        cam.target=object;
                }

                private function onEnterFrame(e:Event):void
                {
                        var cameraSpeed:Number=0.3;

                        
//cam.targetpanangle=-((mouseX-(stage.stageWidth/2))*0.1);
                        
//cam.targettiltangle=-((mouseY-(stage.stageHeight/2))*0.1);

                        cam.view;
                        view.render();
                }
        }
}