title: Use Struts2 property tag in DisplayTags
body: <p>I'm trying to render a table using DisplayTag. Everything works normally when I render a column in the usual manner:</p>
  
  <pre><code>&lt;display:column property="id_material" title="ID" /&gt;
  </code></pre>
  
  <p>Now, i want one column to show 2 properties concatenated. So I tried using the &lt; s:property > tag:</p>
  
  <pre><code>&lt;display:column title="UNIDAD"&gt;&lt;s:property value="property1"/&gt; &lt;s:property value="property2"/&gt;&lt;/display:column&gt;
  </code></pre>
  
  <p>But no value is showed in the column. Is there an alternative way to do this?</p>