[away3d] Away 3D Lite : alpha and layers

[PW]

I have a number of planes that are being added to an
ObjectContainer3D.

//
planesHolder = new ObjectContainer3D();
bitmapMaterial = new BitmapFileMaterial("images/note.png");
bitmapMaterial.smooth = true;
//
//
for (var k:int = 0; k < 10; k++)
{
        var plane3:Plane = new Plane(bitmapMaterial,73,82);
        planes3.push(plane3);
        planesHolder3.addChild(plane3);
}
//

Now I have tried adding layers for each plane like so:

plane3.layer = new Sprite();
view.addChild(plane3.layer);
plane3.layer.alpha = .2;

And have also tried adding a layer to the ObjectContainer3D:

planesHolder3.layer = new Sprite();
view.addChild(planesHolder3.layer);
planesHolder3.layer.alpha = .2;

In both cases, I later add the planesHolder (ObjectContainer3D) to the
scene.

view.scene.addChild(planesHolder3);

However, no alpha properties are being applied for any of the planes.
Can someone point to what I'm doing incorrectly please?

Thanks.