How to change Color of ASP.Net AJAX Bar Chart Bars

Hello Sir,

I added pie chart and bar chart into my website which fetched data from database. but now i am facing problem of how i can change colour of bar chart pillers to grey colour plz help me.

i used this artical for bar chart

http://www.aspsnippets.com/Articles/ASPNet-AJAX-Bar-Chart-Control-Populate-from-Database-example.aspx