I want to have this table with column1 and column2 sorting by richfaces, but the sorting do not appear.

Can someone help? Thanks.

column1 | column2 | column3 |
value1 | value2 | s1 | s2 | s3 |
value1 | value2 | s1 | s2 | s3 |
value1 | value2 | s1 | s2 | s3 |
value1 | value2 | s1 | s2 | s3 |
value1 | value2 | s1 | s2 | s3 |
value1 | value2 | s1 | s2 | s3 |

My code is:

<rich:dataTable id="table" var="record"
value="#{tableBean.values}" rows="10" width="100%">
<f:facet name="header">

<rich:columnGroup>
<rich:column>
<h:outputText value="Column1" />
</rich:column>

<rich:column>
<h:outputText value="Column2" />
</rich:column>

<rich:column colspan="3">
<h:outputText value="Column3" />
</rich:column>

</rich:columnGroup>
</f:facet>

<rich:column sortBy="record.value1">
<h:outputText value="record.value1" />
</rich:column>


<rich:column>
<h:outputText value="record.value2" />
</rich:column>

<rich:column>
<h:outputText value="record.s1" />
</rich:column>

<rich:column>
<h:outputText value="record.s2" />
</rich:column>

<rich:column>
<h:outputText value="record.s3" />
</rich:column>
</rich:dataTable>

Can someone help? Thanks