inmethod grid - Ajaxically update child grid from Master grid

Hello,

I am using inMethod data grid with Wicket 1.5.

I have a page to show master grid (MasterPanel). MasterPanel has child grid
(ChildPanel) to display child records. ChildPanel accepts MasterBean as one
of the arguments of the Constructor to retrieve child records using Master
PK id.

Now, on selection of row in Master grid, I want to ajaxically refresh child
panel.
I don't want to use Modal Window.

Following is code snippet:

public class MasterPanel extends Panel{

public MasterPanel(String id, IModel<SomeBean>) {
MasterBean masterBean = <<get Master Bean from service method>>;
//form
Form<MasterBean> form = new Form<MasterBean> ("form", new
CompoundPropertyModel<MasterBean>(masterBean));
form.setOutputMarkupId(true);
//Child Panel added into MasterPanel
ChildPanel childPanel = new ChildPanel("child", form.getModel());
childPanel.setOutputMarkupId(true);

form.add(childPanel);
DataGrid<GridList<MasterBean>, MasterBean> grid = masterGrid("grid",
childPanel);
grid.setOutputMarkupId(true);
form.add(grid);

private DataGrid<GridList<MasterBean>, MasterBean> masterGrid(String
property, final ChildPanel childPanel) {
....
....
....
//OnRowClicked in Databgrid
@Override
protected void onRowClicked(AjaxRequestTarget target, IModel<MasterBean>
rowModel) {
getForm().setDefaultModel(rowModel);
target.add(childPanel);

Above code is not refreshing the child as the ChildPanel is already created
at the time of adding into MasterPanel. I want ChildPanel to be re-rendered
using selected MasterBean from Master grid.

Any help/suggestions?

Thanks,
-Mihir.