At work, we had a similar need due to sales and marketing type folks who live in Excel. We first tried add_chart_ext with no success. Next we did some pretty extensive internet searches with various terms but could not find anything suitable in Perl. (This situation may have changed by now though.)

In the end, we succumbed to the Dark Side; we use an older version of POI. (We see no point in upgrading something that has been working for a few years now.)