title: Nested array collections observable is not working in knockout
body: <p>I have company list, when clicking on each company need to show the salespersons of that company. </p>
  
  <p>I tried knockout for this. below is script and the whole you can find in <a href="http://jsfiddle.net/habdulha/gkqeD/29/" rel="nofollow">http://jsfiddle.net/habdulha/gkqeD/29/</a></p>
  
  <p>Initial company is listed but clicking on the company the salespersons are not loaded in. </p>
  
  <pre><code>&lt;!-- language: lang-js --&gt;
  
  var rootViewModel = function(companies) {
  this.companiesModel = ko.observableArray(companies);
  }
  
  var companyModel = function(salesPersonModel) {
  CompanyId = ko.observable();
  Name = ko.observable();
  SalesPersonList = ko.observableArray(salesPersonModel);
  LoadSalesPerson = function() {
  
      var self = this;
      var postData = {
          companyId: this.CompanyId()
      }
      /// ajax to get the emp name based on company id
      var data = $.ajax({
          type: 'GET',
          url: '/echo/json/',
          data: postData,
          success: function(result) {
              /// result is based on companyid
              var ajaxReply = {
                  "empName": "John",
                  "empName": "John 1"
              };
  
  
              self.SalesPersonList = ko.observableArray(ko.mapping.fromJS(ajaxReply)());
  
  
          },
          error: function(xhr, ajaxOptions, thrownError) {
              alert(xhr.status);
              alert(thrownError);
          }
      });
      }
    }
  
   var salesModel = function() {
    empName = ko.observable();
   }
  
  
    var myCompanyModelArray = new Array();
    var mySalesModelArray = new Array();
    mySalesModelArray[0] = new salesModel();
    myCompanyModelArray[0] = new companyModel(mySalesModelArray);
    var mainViewModel = new rootViewModel(myCompanyModelArray);
    ko.applyBindings(mainViewModel);
  
    $(document).ready(function() {
        var data = $.ajax({
        type: 'GET',
        url: '/echo/json/',
        //// get all the companies
        success: function(data) {
          var ajaxReply = {
              {
                  "CompanyId ": "1",
                  "Name ": "Comp 1"
              }, {
                  "CompanyId ": "2",
                  "Name ": "Comp 2"
              }
          };
          residencyViewModel.yearGroupModel(ko.mapping.fromJS(ajaxReply)());
  
      },
      error: function(xhr, ajaxOptions, thrownError) {
          alert(xhr.status);
          alert(thrownError);
      }
     });
  
    });
  </code></pre>