title: How can I use existingResponse="Auto" successfully?
body: <p>So I am returning detailed 400 error responses from my MVC web app.  Setting existingResponse="PassThrough" works, but that's not what I want.  I don't want to expose all failures, I only want to expose them when I have custom responses.</p>
  
  <p>Auto, is set by default, but I deliberately set it. However, the documentation says "SetStatus" flag must be set, but I have no idea how to do such a thing. I wrote the following four controller methods in order to test it, and only BadRequestD works. The others set the status code and the status just fine, but the body content is "Bad Request".</p>
  
  <pre><code>public ActionResult BadRequestA()
  {
      Response.StatusCode = 400;
      return Content("weeeeee");
  }
  
  public ActionResult BadRequestB()
  {
      Response.Status = "400 U DUN MESSED UP";
      return Content("weeeeee");
  }
  
  public ActionResult BadRequestC()
  {
      Response.Status = "400 U DUN MESSED UP";
      Response.StatusCode = 400;
      return Content("weeeeee");
  }
  
  public ActionResult BadRequestD()
  {
      Response.StatusCode = 400;
      Response.TrySkipIisCustomErrors = true;
      return Content("weeeeee");
  }
  </code></pre>