bullets and description at desired point

HTML

<script src="http://www.amcharts.com/lib/3/amcharts.js"></script>
<script src="http://www.amcharts.com/lib/3/serial.js"></script>
<div id="chartdiv" style="width: 100%; height: 362px;"></div>

JavaScript

var lineChartData = [
                {
                    "date": "2009-10-12",
                    "value": 20
                },
                {
                    "date": "2009-10-13",
                    "value": 19
                },
                {
                    "date": "2009-10-16",
                    "value": 25
                },
                {
                    "date": "2009-10-17",
                    "value": 24
                },
                {
                    "date": "2009-10-18",
                    "value": 26
                },
                {
                    "date": "2009-10-19",
                    "value": 27
                },
                {
                    "date": "2009-10-20",
                    "value": 15,
                    "bullet": "square",
                    "description": "Something bad happened!"
                },
                {
                    "date": "2009-10-23",
                    "value": 29
                },
                {
                    "date": "2009-10-24",
                    "value": 28
                },
                {
                    "date": "2009-10-25",
                    "value": 30
                },
                {
                    "date": "2009-10-26",
                    "value": 72,
                    "bullet": "round",
                    "description": "Something good happened!"
                },
                {
                    "date": "2009-10-27",
                    "value": 43
                },
                {
                    "date": "2009-10-30",
                    "value": 31
                },
                {
                    "date": "2009-11-01",
                    "value": 30
                },
                {
                    "date": "2009-11-02",
                    "value": 29
                },
                {
                    "date": "2009-11-03",
                    "value": 27
              ...