Vue.js: viewから配列の要素を参照する

vuejs-propchange.html

<script src="http://cdnjs.cloudflare.com/ajax/libs/vue/0.11.0/vue.min.js"></script>
<div id="container">
  <div>
    0:{{array[0].name}}, {{array[0].prop}}
  </div>
  <div v-repeat="array" v-show="$index > 0">
    {{$index}}:{{name}}, {{prop}}
  </div>
</div>
<script>
  var app = new Vue({
    el: "#container",
    ready: function() {
      var self = this
      setTimeout(function() {
        // it works!
        var f = function(i) {
          var o = self.array[i]
          o.$add("prop", true) // we must use the $add method to add a property
          self.array.$set(i, o) // we must use the $set method to modify an element of array
        }
        f(0)
        f(1)
        f(2)
        
        // it doesn't work!
        // self.array[0].$add("prop", true)
        // self.array[1].$add("prop", true)
        // self.array[2].$add("prop", true)
      }, 1000)
    },
    data: {
      array: [
        { name: "a" },
        { name: "b" },
        { name: "c" }
      ]
    }
  })
</script>