React Router のハンドラーコンポーネントに Props を渡すにはどうすればよいですか?

<code class="javascript">var Dashboard = require('./Dashboard');
var Comments = require('./Comments');

var Index = React.createClass({
  render: function () {
    return (
      <div>
        <header>Some header</header>
        <RouteHandler />
      </div>
    );
  }
});

var routes = (
  <Route path="/" handler={Index}>
    <Route path="comments" handler={Comments}/>
    <DefaultRoute handler={Dashboard}/>
  </Route>
);

ReactRouter.run(routes, function (Handler) {
  React.render(<Handler/>, document.body);
});</code>

<code class="javascript">var CommentsWithProps = React.createClass({
  render: function () {
    return (
      <Comments myprop={this.props.myprop} />
    );
  }
});

// Then in the routes definition:

var routes = (
  <Route path="/" handler={Index}>
    <Route path="comments" handler={CommentsWithProps}/>
    <DefaultRoute handler={Dashboard}/>
  </Route>
);</code>

<code class="javascript">class Index extends React.Component {

  constructor(props) {
    super(props);
  }

  render() {
    return (
      <h1>
        Index - {this.props.route.foo}
      </h1>
    );
  }
}

var routes = (
  <Route path="/" foo="bar" component={Index}/>
);</code>