Flex 3 ColumnChart: dynamically changing the column colors

When using a ColumnChart created in Flex 3, how can I to change the fill color of columns that meet a certain criteria?

Example: I have 8 columns representing agreement percentages between groups of people and want to change the开发者_StackOverflow社区 fill color (or otherwise highlight) of all the columns that have over 80% agreement.

---

Check out the documentation on per-item fills.