title: Can't call $expand on Service Operation result
body: <p>I have Odata service which exposes "StartAction" service operation. This operation returns ActionResponse entity</p>
  
  <pre><code>  &lt;EntityType Name="ActionResponse"&gt;
      &lt;Key&gt;
        &lt;PropertyRef Name="FolderId" /&gt;
      &lt;/Key&gt;
      &lt;Property Name="FolderId" Type="Edm.String" Nullable="false" /&gt;
      &lt;Property Name="ClientData" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="ProcessCaption" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="ProcessName" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="ProjectName" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="ProjectVersion" Type="Edm.Int32" Nullable="false" /&gt;
      &lt;Property Name="ServerData" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="StageName" Type="Edm.String" Nullable="true" /&gt;
      &lt;Property Name="UserName" Type="Edm.String" Nullable="true" /&gt;
      &lt;NavigationProperty Name="Action" Relationship="Metastorm.EngineData.ActionResponse_Action_Action_ActionResponse" FromRole="ActionResponse_Action" ToRole="Action_ActionResponse" /&gt;
    &lt;/EntityType&gt;
   &lt;Association Name="ActionResponse_Action_Action_ActionResponse"&gt;
      &lt;End Role="ActionResponse_Action" Type="Metastorm.EngineData.ActionResponse" Multiplicity="0..1" /&gt;
      &lt;End Role="Action_ActionResponse" Type="Metastorm.EngineData.Action" Multiplicity="0..1" /&gt;
    &lt;/Association&gt;
  </code></pre>
  
  <p>when i try to $expand Action navigation property, i get the following error: </p>
  
  <pre><code>    Query options $expand, $filter, $orderby, $inlinecount, $skip and $top cannot be applied to the requested resource
  </code></pre>
  
  <p>I can work it around if i will return IQueryable with only one item, but is looks ugly. Does anyone know any other way how to make $expand work for Service Operations which return a single entity?</p>
  
  <p>Thanks in advance</p>
  
  <p>P.S. The service have custom implementation</p>