how to set textboxwatermark to textbox if textmode is password in asp.net

Hi,
i have login page contains two textboxes one for username and another one for password i have set textboxwatermark by usign ajax control for username its working fine but when i set to password textbox it shows in encoded form becoz of i set textmode= password so how to resolve this problem plz give solution
<asp:TextBox ID="txtPassword" Width="220px" runat="server"  TextMode="password" CssClass="txtPassword" ToolTip="Enter Password" >
<asp:TextBoxWatermarkExtender ID="TextBoxWatermarkExtender2" runat="server" TargetControlID="txtPassword" WatermarkText="Enter Password">
</asp:TextBoxWatermarkExtender>
thanks in advance,
Raghu.
...