Dynamically modifying pie slice color using ember

I have a donut chart (rendered using Highcharts) on which I am trying to achieve a behavior similar to sunburst chart in d3.js. Here is the jsfiddle code:

On hovering over a pie slice, I wish to reduce the transparency of all other slices other than one over which the mouse is hovering.I have managed to iterate and change the slice color.I have also defined an observer in ember for the series object. So ideally when this object changes, my updateSeries function must be called and color change must take effect dynamically.

Why is my series not being updated dynamically by ember? Is there something which I am missing?