Custom Legends for Chart

Hi,

We are using version Extjs 4.2.2

I have a chart with line series and legend. By default legend shows just the value of yField. I am trying to show some more information in the legend along with the yField value as follows:

legendItem1

Total: xxxxx

Avg: xxxxxx

legendItem2

Total: xxxxx

Avg: xxxxxx

Is there a way?

Thanks

Santosh