I just found the solution !
1) bind the tabbedpane to your bean : <x:panelTabbedPane binding="#{yourbean.tabbedPane}" > </x:panelTabbedPane>
2) make an init function called by the constructor of your bean :
private void initTabbedPane() {
// New tabbedPane
tabbedPane = new HtmlPanelTabbedPane();
// Your panelTabs
HtmlPanelTab tab0 = new HtmlPanelTab();
tab0.setLabel("Je suis tab0");
HtmlPanelTab tab1 = new HtmlPanelTab();
tab1.setLabel("Je suis tab1");
// Just get the list of children to add it your own panelTabs
List children = tabbedPane.getChildren();
children.add(tab0);
children.add(tab1);
}
Thanks
Bye
Gilles

