How to bound ajaxListener tag with the ajaxListener method

[svenhassel]

Hi,
I don't understand why this <a4j:ajaxListener> example doesn't work:

<rich:panel>
 <f:facet name="header">Using a4j:actionListener</f:facet>
 <a4j:commandButton value="Submit" reRender="#{ajaxBean.areas}">
 <a4j:ajaxListener type="echo.AjaxBean"/>
 </a4j:commandButton>
</rich:panel>
<h:panelGrid>
 <h:outputText id="id1" value="id1"/>
 <h:outputText id="id2" value="id2"/>
</h:panelGrid>

package echo;

import java.util.HashSet;
import java.util.Set;

import org.ajax4jsf.event.AjaxEvent;

public class AjaxBean implements org.ajax4jsf.event.AjaxListener{

 private Set<String> areas = new HashSet<String>();

 public Set<String> getAreas() {
 return areas;
 }

 public void setAreas(Set<String> areas) {
 this.areas = areas;
 }

 public void processAjax(AjaxEvent event) {
 System.out.println("Update IDs of components to be rerendered");
 areas.add("id1");
 areas.add("id2");
 }

}

I will thank any suggestion...