Trying to post an XForm and all I'm getting is 404.

Trying to use code similar to what is found in this thread, http://world.episerver.com/Modules/Forum/Pages/Thread.aspx?id=64533&pageIndex=2

// Controller

public class StandardController : PageControllerBase<StandardPage>
  {
    private readonly XFormPageUnknownActionHandler _xFormPageUnknownActionHandler;

    public StandardController()
    {
      _xFormPageUnknownActionHandler = new XFormPageUnknownActionHandler();
    }

    [HttpGet]
    public ActionResult Index(StandardPage currentPage)
    {
      return View(currentPage);
    }

    [HttpPost]
    public ActionResult XFormFailed(StandardPage currentPage, XFormPostedData xFormPostedData)
    {
      return View("Index", currentPage);
    }

    [HttpPost]
    public ActionResult XFormPost(XFormPostedData xFormPostedData)
    {
      return _xFormPageUnknownActionHandler.HandleAction(this);
    }

    [HttpPost]
    public ActionResult XFormSuccess(StandardPage currentPage, XFormPostedData xFormPostedData)
    {
      return View("Index", currentPage);
    }

  }

// View

@Html.PropertyFor(model => model.MainForm, new
{
  XFormParameters = new XFormParameters
  {
    PostController = "Standard",
    SuccessAction = "XFormSuccess",
    FailedAction = "XFormFailed",
    PostAction = "XFormPost"
  }
})

Could someone explain how the process of taking care of XForms works, so I understand it? It's hard to write code for things you don't know. =)