Instead of using, .rangeSelector({settings})use the function .clickButton:
chart.rangeSelector.clickButton(0,{type: 'month', count: 1},true);
However, this function seems somewhat strange and undocumented from what I can say.
It takes the following arguments:
* @param {Number} i The index of the button
* @param {Object} rangeOptions
* @param {Boolean} redraw
redraw true, i ( , , ). , , Options, . , 1 . :
* millisecond
* second
* minute
* hour
* day
* week
* month
* ytd
* year
* all
, .destroy(); , , , , .
JSFiddle, : http://jsfiddle.net/HFPr2/