Panel child center

Hello,

how to center a child in a panel ?

var panel:Panel = new Panel();
var button:Button = new Button();
button.label = "child";
panel.addChild( button );
this.addChild( panel );

Thanks.

H/VLayout verticalAlign = VerticalALigh.MIDDLE
&
H/VLayout horizontalAlign = VerticalALigh.CENTER

AnchorLayout with AnchorLayoutData using verticalCenter=0, horizontalCenter=0.

Thanks