how to display Ajax Calendarextender control on a Ajax ModalPopupExtender control

<table>
           <tr>
               <td>
                   <asp:label id="UserName" runat="server" font-bold="true" forecolor="#97b23c" font-size="14px" xmlns:asp="#unknown"></asp:label>
                   <br />
                   <asp:button id="SelectDtBtn" runat="server" text="Select Date" xmlns:asp="#unknown" />
               </td>
               <td>
                   <asp:panel id="Pnl" runat="server" style="height: 150px; width: 300px; padding: 400 0 0 300;<br mode=" hold=" />                        background-color: #EEE8AA;" xmlns:asp="#unknown">
                       <h4>
                           Emp Joining Details .....</h4>
                       enter date
                       <asp:textbox id="txtdate" runat="server" cssclass="rtlable" width="100px" enabled="true"></asp:textbox>
                       <asp:calendarextender id="ceeFlwUpDate" runat="server" targetcontrolid="txtdate">
                           Format="dd-MMM-yyyy">
                       </asp:calendarextender>
                       <asp:button id="CancelBtn" runat="server" text="Cancel" /><br />
                   </asp:panel>
                   <asp:modalpopupextender id="MPEUserList" runat="server" targetcontrolid="SelectDtBtn" xmlns:asp="#unknown">
                       PopupControlID="Pnl" DropShadow="false" CancelControlID="CancelBtn" BackgroundCssClass="ModalPopupBG">
                   </asp:modalpopupextender>
               </td>
           </tr>
       </table>