Thanks for the reply,i have done it myself, but with some additional work which is needed to set the GridvVewHeaderIndentCell background.
the problem is,
in my application i use Vista theme for all other controls without customization(ex:scrollbars,buttons),
i use the below code to acheive it
StyleManager.ApplicationTheme = ThemeManager.FromName("Vista");
when this is set, the custom style for GridVewHeaderIndentCell is overidden,
i added the above code to app.xaml constructor of the example in the link u sent , the same problem is happening.
(Note: all other custom styles are applied except GridVewHeaderIndentCell style).
to fix this i have to set the Theme programatically to each UI element separately, insted of setting it to the application.
this costs me additional code ,just to acheive a single style..
Hope u understand my problem..
if the there is something wrong with my implementation kidly advice else kindly make a note of the problem..