chart_map_modifier in DBD::Chart

Hello,

does anybody on this list use DBD::Chart?

I have the problem that concerns modifying HTML imagemap elements. I
have barchart on depts' costs. When I click on a bar I have dept's name
in :X parameter and its cost value in :Y. But I would like to have
deptid in :X instead of dept name.

The author of DBD::Chart mensions about 'chart_map_modifier'
attribute to make it. But I have big problem with it. Does anbody has
any examples with using 'chart_map_modifier'?

Thank you for your help,
Wojciech Pietron
.