I need to set the rounded corners inside the grid control using silverlight 4. wehn i tried to do something like this

 <Border BorderThickness="2" BorderBrush="#FF3EA9F5" Grid.Row="1" CornerRadius="5,5,0,0" Height="10" VerticalAlignment="Bottom">
                <Grid  x:Name="Phani1" Width="auto"> </Grid>
            </Border>

i am able to see rounded corners outside the gird. but i want to grid to appear asa rectangel from outside border. but inside corners of the grid should appear as rounded.

Please let me knowhow to do that if anyone had any idea on that.

Thanks in advance.