ext:DateField in updatepanel

Hi All,

I know Updatepanel is quite a known issue.
I hope someone can help me out?

I am using ext Datefield in updatepanel.

<ext:ResourceManager ID="ExtScriptManager1" runat="server" InitScriptMode="Linked">
</ext:ResourceManager>
<asp:ScriptManager runat="server" ID="ScriptManager1">
</asp:ScriptManager>

<asp:UpdatePanel ID="updpnlSubDateExpires" runat="server">
<ContentTemplate>
<table cellpadding="0" cellspacing="0" border="0">
<tr>
<td>
<ext:DateField runat="server" ID="cdeExpirationDateToAccumulate" Format="dd/MM/yyyy"
MaxLength="10" Width="150px"></ext:DateField>
</td>
<td>
<asp:TextBox runat="server" ID="tbTimeToAccumulate" CssClass="TextBoxNormalCoolite"
MaxLength="5" Width="60px"></asp:TextBox>
<cc1:MaskedEditExtender ID="MaskedEditExtender2" runat="server" Mask="99:99" MaskType="Time"
AcceptAMPM="false" TargetControlID="tbTimeToAccumulate">
</cc1:MaskedEditExtender>

</td>
<td>
<asp:Button runat="server" ID="btnAccumulateExpirationDates" CausesValidation="false"
Text="Accumulate Expiration Dates" OnClick="btnAccumulateExpirationDates_Click" />

</td>
</tr>
</table>

</ContentTemplate>
</asp:UpdatePanel>

On server side.

On click of button btnAccumulateExpirationDates_Click is fired.
And i have some Database update.
But my problem is after the click the ext:Datefield cdeExpirationDateToAccumulate disappears.
Obivisouly asp:textbox tbTimeToAccumulate works fine and appears.

I tried

this.ExtScriptManager1.AddUpdatePanelToRefresh(upd pnlSubDateExpires);
on my Page_Load();

I would appreciate any help.

Thanks

Menon