title: passing parameters to RIA service from extjs with json end point
body: <p>I am trying to communicate with RIA service from extjs using POST for getting response with following code.</p>
  
  <pre><code>var store = Ext.create('Ext.data.Store', {
                          model: 'RootResults',
                          proxy: {
                              type: 'ajax',
                              actionMethods: 'POST',
                              url: 'MyService.svc/JSON/GetRes',
                              headers: {
                                  'Content-type': 'application/json' 
                              },
                              reader: {
                                  type: 'json',
                                  root: 'GetResResult.RootResults',
                                  totalProperty: 'GetResResult.TotalCount'
                              }
                              , pageParam: undefined,
                              startParam: undefined,
                              limitParam: undefined
  
                              , success: function (response) {
                                  alert(response);
  
                              }
  
                          }
                      });
  
       var operation = new Ext.data.Operation({
            FId: 1,
            SId: 0
        });
  
   store.load({ params: Ext.encode(operation) });
  </code></pre>
  
  <p>i can access it with get.
  when i am trying with POST, it returning error - "405 Method Not Allowed".
  what to do to make it POST enabled?</p>