Tooltip setting for Combination Chart

Hi Experts,

We have a combination chart which is displaying previous and current year trend . we have got the data in one bex query using cells , so in columns we are getting the O/P as below

                         Current             Previous

JAN 2015           100                     80

FEB  2015           120                     70

MAR 2015            80                      60

When we enable the tooltip it shows the same month/year for both the current and previous column and line .

I tried to check if there is a way to modify the tooltip to show the previous year  for line chart.But only saw ways to modify the format the tooltip and not a way to modify the data in it .Is there a way to do so ?

Regards,

Rahul