touchkit toolbar - how to center buttons...

using 7.4.2 and 4.0.0 - i need help on how to make the tool bar full width and with buttons centered - tried just about everything…

Toolbar toolbar = new Toolbar();
HorizontalButtonGroup buttons = new HorizontalButtonGroup();

Button listButton = new Button(“Add Item”);
buttons.addComponent( listButton);

Button detailButton = new Button(“Detail”);
buttons.addComponent( detailButton);


no need for bgroup
add buttons to toolbar