Creating HDividerGroup in AS

Hi,

I'm testing HDividerGroup (spark.containers) and I have problem with
initialize this component from ActionScript like this:

var _hDividerGroup:MyHDividerGroup = new MyHDividerGroup();

for (var j:Number = 0; j < _cols; j++) {
var _group:Group = new Group ();
_hDividerGroup.addElement(_group);

Then I get error: atLeastTwoChildrenRequiredError.

Making the same in MXML working good.