a4j:support within s:selectItems is not working properly....plz help

[suzan.dj0]

<rich:comboBox selectFirstOnUpdate="false" defaultLabel="Enter some value" directInputSuggestions="true">

     <s:selectItems var="subMenuList"

          value="#{menuGeneratorView.getList()}"

          itemValue="#{subMenuList.getName()}">

          <a4j:support event="onchange"

                    action="/ClientMastList.xhtml"

                    actionListener="#{menuGeneratorView.setSubMenuHead(subMenuList.getName())}"

                    reRender="bodyHead,body,hlp"/>

     </s:selectItems>

</rich:comboBox>