I can't give a Panel instance as a parameter to a Page constructor anymore in the new setup. Was this already thought of? For instance:
Panel panel = new BarPanel(someSpecialModel);
Page foo = new FooPage(panel);
setResponsePage(page);
you have it backwards. you pass in the parent not the child.
Page foo=new FooPage();
new BarPanel(foo, "id");
setResponsePage(foo);
-Igor