title: Updating view model from object not working
body: <p>I want to be able to observe an object inside the view model. I have a simple example that doesn't work as expected, can anyone see the problem?</p>
  
  <p>Using knockout 1.1.1, have 2 inputs as such:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;form data-bind="submit: save"&gt;
      &lt;input type="text" data-bind="value: deckName" /&gt;
      &lt;input type="text" data-bind="value: deck().Name" /&gt;
      &lt;button type="submit"&gt;Go&lt;/button&gt;
  &lt;/form&gt;
  </code></pre>
  
  <p>When the page loads, the inputs get the default values, but on submitting the form <code>viewModel.deck().Name</code> is not updated but <code>viewModel.deckName</code> is.</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;script type="text/javascript"&gt;
      var initialData = {"Name":"test"};
  
      var viewModel = {
          deck: ko.observable(initialData),
          deckName: initialData.Name,
          save: function() {
              ko.utils.postJson(location.href, { deck: this.deck, deckName: this.deckName });
          }
      };
      ko.applyBindings(viewModel);
  &lt;/script&gt;
  </code></pre>
  
  <p>On the form POST, <code>deck</code> will still send "test" no matter the input whilst <code>deckName</code> will be the corresponding input value. </p>
  
  <p>What I really want is to be able to observe an object <code>viewModel.deck</code> and then bind its properties to inputs, but the properties don't get updated.</p>