I recently started using Fusioncharts gantt chart and also needed to have the labels in the tasks.
As a work around I added two tasks, one for the actual task, and one for the label. For the label task I set the color to #00000000 and the alpha to 0 to get an invisible task, but the label still renders, used some calculations of the original task height and topPadding to position task two's label over center of task one.
Would be nice to have this as a feature instead of hacking it up.