In some languages text has to be displayed in right to left direction.
For this case we don't have any property supported by XAML, Java script.
To achieve it we can use following traditional way.
char str = mystr.Text.ToCharArray();
mystr.Text = new string(str);
mystr.Text = mystr.Text.split('').reverse.join('');
Hope It could be useful for silverlight lovers. Please post your comments bellow.