p: summaryRow does not work with p: columns

I have a JSF page with a p:columns to show data analytically and a p:summaryRow to show the summary.

It happens that inside my p:summaryRow , I have p:columns , because I can not predict how many results I'll have, so I need to use dynamic columns.

But when I load the page, this p:columns is not shown. In fact, the method where I get the data from the Bean is never called.

<p:dataTable value="#{storeBean.segmentsByStore}" var="segmentsByStore"
                     sortBy="#{segmentsByStore.segment}">
<p:summaryRow>
    <p:column colspan="3" style="text-align: right">
        <h:outputText value="TOTAL OF #{segmentsByStore.segment}"/>
    </p:column>
    <p:columns value="#{storeBean.totalStoreSaleDates}" var="saleDate">
        <h:outputText
                value="#{storeBean.totalStoreSales.get(saleDate).get(segmentsByStore.segment).value}">
            <f:convertNumber type="currency"/>
        </h:outputText>
    </p:columns>
</p:summaryRow>
</p:dataTable>