title: NHibernate fetch="join" mapping attribute does not appear to work
body: <p>Mapping a dictionary with NH. Declaration is as follows:</p>
  
  <pre><code>&lt;hibernate-mapping ...
      &lt;map 
          name="CostsByRole" 
          table="JobAccountingSnapshotCosts"
          lazy="false" 
          fetch="join" 
          access="nosetter.camelcase-underscore"&gt;
              &lt;key column="SnapshotId" /&gt;
              &lt;index column="RoleCode" type="String" /&gt;
              &lt;element column="Amount" type="Decimal" /&gt;
      &lt;/map&gt;
  &lt;/hibernate-mapping&gt;
  </code></pre>
  
  <p>I am expecting a single SQL query to be generated but instead I get two: a select for the actual object, followed by a select for the contents of the dictionary.</p>
  
  <p>Any ideas?</p>