[away3d] changing material of an obj

[kakarlus]

i have a problem on changing the material of a loaded .obj file...
the material: mat on the obj does not work, but it works on the
cylinder...

var mat:BitmapMaterial = new BitmapMaterial(bitmapData);

                        for(var i:uint = 0 ; i < bodyParts.length ; i++){
                                obj = Obj.load(bodyParts[i], {material:mat, 
loader:Object3DLoader,
bothsides:false});
                                objContainer.addChild(obj);
                                obj.scale(1);
                                obj.y = -150;
                        }
                        var cylinder = new Cylinder({material:mat/*new 
ColorMaterial
(0xFF0000)*/, radius:25, height:100, segmentsW:16});
                        //cylinder.material = mat;
                        objContainer.addChild(cylinder);