Change DataGrid Scroll Colors

I’m using the MX04 DataGrid component and have managed to set all the other styles the way I want but have had trouble changing the colors used by the scrollbar.

So far I’ve been using code similar to this:

//
//
myDataGrid.setStyle("backgroundColor", 0xFF0000);
//
//

Can anyone help me change the colors of MyDataGrid’s scroll bar?

Thanks.