<rich:column sortBy="#{model.modVal}" label="Model Value"
    sortable="true" id="modelVal"  rendered="#{backingBean.renderMap['modVal']}">
    <f:facet name="header">
    <h:outputText value="Model Value" />
        <h:graphicImage title="Filter"
            value="#{backingBean.dataModel.modValFilter }">
            <a4j:ajax event="click" render="filterCol"
        execute="@form"
        listener="#{backingBean.loadModalPanelData('modVal') }"
        oncomplete="#{rich:component('filterCol')}.show()">
        </a4j:ajax>
        </h:graphicImage>
        </f:facet>
<h:outputText value="#{model.modeVal}"
title="#{model.modelVal}" />
</rich:column>

<f:facet name="header">
   <h:panelGrid>
      <h:outputText value="Model Value"/>
      <h:graphicImage title="Model Filter"/>
   </h:panelGrid>
</f:facet>