title: Retrieve empty column using ColumnSet
body: <p>I need to retrieve certain columns of an Entity even if the field is not populated.</p>
  
  <p>I tried (serv is an OrganizationService object) :</p>
  
  <pre><code>Entity entity = serv.Retrieve(entityName, entityId, new ColumnSet(true));
  </code></pre>
  
  <p>and</p>
  
  <pre><code>Entity entity = serv.Retrieve(entityName, entityId, new ColumnSet(new String[] { "my_column" }));
  </code></pre>
  
  <p>But, "my_column" has not been set yet, so in my object "entity", I can't access to it and get it's type (for exemple).</p>
  
  <p>I do need to get it even if it's empty, because after that, I need to get the entity referenced by this field when it's a lookup.</p>
  
  <p>Hope it makes sense !</p>
  
  <p>Thanks for your replies !</p>