title: WCF REST WebService content type is wrong
body: <p>I created a simple REST Service using the WCF REST Template 40(CS) which is working just fine. There only is a problem that the response uses "application/json" as content type but I need "text/plain".</p>
  
  <p>The problem is already explained in a blog post but because of the template I'm not using a .svc file. So the proposed solution does not work for me.</p>
  
  <p>My Service contract:</p>
  
  <pre><code>[ServiceContract]
  public interface ICouchService
  {
      [OperationContract]
      [WebInvoke(ResponseFormat = WebMessageFormat.Json, UriTemplate = "/", Method = "GET")]
      ServiceInformation Hello();
  
      [OperationContract]
      [WebGet(ResponseFormat = WebMessageFormat.Json, UriTemplate = "/piclib/{id}")]
      CouchDocument GetDocument(string id);
  }
  </code></pre>
  
  <p>web.config:</p>
  
  <pre><code>&lt;system.webServer&gt;
      &lt;modules runAllManagedModulesForAllRequests="true"&gt;
        &lt;add name="UrlRoutingModule" type="System.Web.Routing.UrlRoutingModule, System.Web, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a" /&gt;
      &lt;/modules&gt;
    &lt;/system.webServer&gt;
  
    &lt;system.serviceModel&gt;
      &lt;serviceHostingEnvironment aspNetCompatibilityEnabled="true"/&gt;
      &lt;standardEndpoints&gt;
        &lt;webHttpEndpoint&gt;
          &lt;standardEndpoint name="" helpEnabled="true" automaticFormatSelectionEnabled="false"/&gt;
        &lt;/webHttpEndpoint&gt;
      &lt;/standardEndpoints&gt;
    &lt;/system.serviceModel&gt;
  </code></pre>