i found it :)
i make the code if someone have the same problem
override protected function
generateGraphic(feature:Feature):DisplayObject {
var label:TextField = new TextField();
label.autoSize = TextFieldAutoSize.LEFT;
var _model:Model=Model.getModel();
var px:Pixel = new Pixel();
px =
_model.map.getMapPxFromLocation(feature.geometry.bounds.center);
label.x =px.x; // here you can define the y offset
label.y = px.y;// here you can define the x offset