[flexcomponents] Set background row color in Adv. DataGrid

[reflexactions]

I am trying to change the background color of rows in a custom version 
of the ADG. 

I have overidden "drawRowBackground" which provides the rowIndex and 
dataIndex parameters.

With a standard DataGrid it is simple given the dataIndex to find the 
particular data item the row is displaying.

However with an AdvancedDataGrid displaying hierachical data how can I 
use the dataIndex or rowIndex to access the related data item?

Thanks.