How to add image and HTML in the Footer of Highcharts in View and Export using GWT?

[KARTIKEYAN]

I have created a Chart and Data table.
I need to add few custom texts like date and an image in the end of the chart and that to be appear in export as well.
I have found the following example
http://jsfiddle.net/ur02w4j5/12/

where,

var label = this.renderer.label("This text will adjust to chart resizing " +
        "and redraws and will be visible on exported images.")
      .css({
        width: '400px',
        fontSize: '9px'
      })
      .attr({
        'stroke': 'silver',
        'stroke-width': 1,
        'r': 2,
        'padding': 5
      })
      .add();

    label.align(Highcharts.extend(label.getBBox(), {
      align: 'center',
      x: 20, // offset
      verticalAlign: 'bottom',
      y: 0 // offset
    }), null, 'spacingBox');

does the additional text to appear
But I am not able to find the corresponding APIs in GWT highcharts-v1.7.0.
I have tried the following APIs.

    String lefttext = "<label class=\"float-left\">Left</label>";
    String symbol = "<span class=\"float-right\"><label>Right:</label><span class=\"img-css\"></span></span>";
    chart.setLabelItems( new LabelItem().setHtml( lefttext + symbol ) );

This didn't work!!
Please Help!

If there is no support available also please let me know .
I am not able to find anywhere in the web. :(