Trying to truncate chart axis label text & add tooltip

[mschiavone]

I have a bar chart that can have very long values for the Y axis labels. I'd like to truncate those labels and allow the user to roll over the truncated label to see a tooltip containing the full text. Truncating was no problem, but I'm having problems implementing the tooltip - not sure how to access the label text from my custom labelRenderer. The labelRenderer extends ChartLabel. I also thought about using a function for the tooltip (in the MXML), but not sure how to access the label text there either. Any thoughts on how to do this?