replace Panel inside a Form

[Benjamin Ernst]

Hi,
I am trying to replace a Panel, which is inside a Form, which is inside a
Page, which is inside a ModalWindow.
The first time it works fine, but when I want to replace it a second time,
the Panel has no parent.

Here is the code:

listItem.add(new AjaxButton("pflege", MitarbeiterForm.this) {

                        @Override
                        protected void onSubmit(AjaxRequestTarget target,
Form form) {
                            EinsatzPanel newPanel = new
EinsatzPanel("einsatzPanel", ein);
                            newPanel.setOutputMarkupId(true);
                            einsatzPanel.replaceWith(newPanel);
                            target.addComponent(newPanel);
                        }
               });

An here is the Error:

2007-08-24 14:53:18,681 ERROR [http-8080-Processor24]
org.apache.wicket.RequestCycle: This method can only be called on a
component that has already been added to its parent.
java.lang.IllegalStateException: This method can only be called on a
component that has already been added to its parent.
    at org.apache.wicket.Component.replaceWith(Component.java:2224)
    at
de.csg.fips.fe.anzeige.mitarbeiter.pflege.MA_PflegePage$MitarbeiterForm$1$1.onSubmit
(MA_PflegePage.java:251)
    at org.apache.wicket.ajax.markup.html.form.AjaxButton$1.onSubmit(
AjaxButton.java:82)

I don´t know why it only works one time.

Thanks for any help in advance,

Benjamin