We can show the green progress bar in windows phone 8, i have successfully done.
i made the IsDeterminate Proterty as false and bind the progresschanged event values to the Value property of my progressBar. its working superb.
<ProgressBar x:Name="myProgressBar" IsIndeterminate="True" VerticalAlignment="Center" Visibility="Visible" Width="900" TextOptions.TextHintingMode="Animated" CharacterSpacing="2"/>
It is working as i wanted. simple, easy and superb control....