title: Alfresco 5.0.a - custom search facet
body: <p>I'd like to add some custom facets to the Alfresco (version 5.0.a) search page. I've created an extension which allows to override already created facets:</p>
  
  <pre><code>&lt;import resource="classpath:/alfresco/site-webscripts/org/alfresco/share/imports/share-header.lib.js"&gt;
  &lt;import resource="classpath:/alfresco/site-webscripts/org/alfresco/share/imports/share-footer.lib.js"&gt;
  var facet = widgetUtils.findObject(model.jsonModel, "id", "FCTSRCH_FACET_DESCRIPTION");
  facet.config.label = "Document type";
  facet.config.facetQName = "{http://www.someComp.com/model/comp/1.0}personGroup";
  </code></pre>
  
  <p>But it is not the right way I think.
  The problem is that I cannot override the parent widgets, since they don't have ids (faceted-search.get.js). 
  How do I manage to add a custom facet to the model?</p>
  
  <hr>
  
  <p>Another question is regarding parameter of the facet with name <code>facetQName</code>. In the same file (faceted-search.get.js) I met some strange syntax which I don't understand.
  Some examples:</p>
  
  <pre><code>facetQName: "{http://www.alfresco.org/model/content/1.0}creator.__.u",
  facetQName: "{http://www.alfresco.org/model/content/1.0}modifier.__.u",
  facetQName: "{http://www.alfresco.org/model/content/1.0}description.__",
  </code></pre>
  
  <p>What do these <code>.__.u</code> and <code>.__</code> suffixxes mean?</p>