Hello - I have oracle developer 6i and oracle database 10g.

Hello - I have oracle developer 6i and oracle database 10g.
In the report I want to display the chart's bars or the lines in
different colors depending on the values.
For example employee in sales department whose salary over 1000 $
and have commission will display in red color while the
employees who has the same properties but his salary is equal to
1000 $ will display in green color, and the employees who has
the same properties but his salary is below 1000 $ will display
in blue color
how can i make graphic builder do that?
regards