hi , I have some trouble in Sprite3d !

  I do my 2d ARPG game in flash ,so my avartar bitmap is min rect

I can mark it with offsetX offsetY   width height
so in a bitmap movie   offsetX offsetY can help me to make a perfect
bitmap Movie !
now ,in my 2d game with 3dMoel (2d scene—made by starling ) 3d model for hero) ,  I want to create game skill effect in 3d model avatar !

But my Skill is 2d , so I use Sprite3d for my game skill effect!

my 2d movie bitmap have   offesetX offsetY width height propery !
like it

public function updateBitmapData(bitapData:BitmapData,offsetX:Nunber,offsetY:Number)
{
  bitmap.bitmapData=bimapData;
bitmap.x =offsetX;
bitmap.y=offsetY;

}

I changeit into   a   big bitmap(may be 2048*2048) ,, and mark it uv offsetx offsetY

  now it has   uv data in big bitmap! now I can do the movie ! but I have to use offsetX offsetY to offset it in a right way ! I don’t know how to use it in sprite 3d

I use it like 2d   :

sprite3d.x=offsetX;
sprite3d.y=offsetY;
but the result is wrong !  but it well in flash 2d Sprite

sprite3d has z propery I don;t know how use it ! just like 2d

my camera len is :OrthographicOffCenterLens
  var lens:OrthographicOffCenterLens=new OrthographicOffCenterLens(-Math.ceil(_stage.stageWidth / 2), Math.ceil(_stage.stageWidth / 2), -Math.ceil(_stage.stageHeight / 2), Math.ceil(_stage.stageHeight / 2));

so :
I just want to set offestX offsetY   jus like in 2d flash ,how to convert it in sprite3d ?