title: Knockout manual subscription does not get triggered
body: <p>I've just started a project where I'm trying to use knockout for my viewmodel bindings. But I have a problem where I'm not able to get the view model to react to changes (through manual subscription) made in the view on the selectbox.</p>
  
  <pre><code>var viewModel = function() {
     var self = this;
     self.project = ko.observable();
     self.contractBorders = ko.observable();
  
     self.contractBorders.subscribe(function (newvalue) {
         alert('something changed!');
     });
  };
  
  viewModel.load = function() {
  var data = {"project":{"name":"Project XYZ",
  "number":338,"id":1,"isNew":false},"contractBorders":[{"name":"Border 1 grund","id":1},   
  {"name":"Border 2","id":2},{"name":"Border 3","id":3}]}
  
  viewModel.loadView(data);
  
  };
  viewModel.loadView = function(data) {
      self.project = ko.mapping.fromJS(data.project);
      self.contractBorders = ko.mapping.fromJS(data.contractBorders);
      ko.applyBindings(viewModel);    
  };
  
  viewModel.load();
  </code></pre>
  
  <p>Im expecting the "self.contractBorders.subscribe" to be executed but it never happens. Im I doing it totally wrong?</p>
  
  <p>I've created a Fiddle to reproduce the problem <a href="http://jsfiddle.net/vinblad/6zzSy/6/" rel="nofollow">here</a></p>
  
  <p>Any help would be appreciated!</p>
  
  <p>/BR Vinblad </p>