Problem with ModalPopupExtender and Windows Azure

Hello everyone.

I have a Web portal where the WebForm have this structure.

<%@ Page Title="" Language="vb" AutoEventWireup="false" MasterPageFile="~/Site.Master" CodeBehind="wfCargoIni.aspx.vb" Inherits="SI_LXC.wfCargo" %><%@ Register Src="../Controles/wuc_MenuLateral.ascx" TagName="wuc_MenuLateral" TagPrefix="uc1" %><%@ Register Src="../Controles/wuc_Mensaje.ascx" TagName="wuc_Mensaje" TagPrefix="uc2" %><asp:Content ID="HeadContent" ContentPlaceHolderID="HeadContent" runat="server"><script type="text/javascript">
        var ModalProgress = '<%= ModalProgress.ClientID %>';             </script></asp:Content><asp:Content ID="FeaturedContent" ContentPlaceHolderID="FeaturedContent" runat="server"></asp:Content><asp:Content ID="BodyContent" ContentPlaceHolderID="MainContent" runat="server"><script type="text/javascript" src="../Scripts/jsUpdateProgress.js"></script><asp:Panel ID="panelUpdateProgress" runat="server" CssClass="updateProgress"><asp:UpdateProgress ID="UpdateProg1" DisplayAfter="0" runat="server"><ProgressTemplate><div style="position: relative; top: 30%; text-align: center;"><img src="../Images/gif.gif" alt="Procesando" /><asp:Label ID="lblProcesando" runat="server" Text="Procesando ..."></asp:Label></div></ProgressTemplate></asp:UpdateProgress></asp:Panel><ajaxToolkit:ModalPopupExtender ID="ModalProgress" runat="server" TargetControlID="panelUpdateProgress"
        BackgroundCssClass="modalBackground" PopupControlID="panelUpdateProgress" Enabled="True"></ajaxToolkit:ModalPopupExtender><asp:UpdatePanel ID="UpdatePanel1" runat="server"><ContentTemplate><div class="AsideLeft"><uc1:wuc_MenuLateral ID="wuc_MenuLateral1" runat="server" /></div><div class="AsideRight"><h1><asp:Label ID="lblTituloPpal" runat="server" Text="Listado de Cargos para Empleados"></asp:Label></h1><br /><asp:GridView ID="gvCargo" runat="server" AutoGenerateColumns="False" ShowFooter="true"><HeaderStyle HorizontalAlign="Center" CssClass="report-main-header" /><RowStyle CssClass="report-item" /><PagerStyle CssClass="report-main-header" /><FooterStyle CssClass="report-main-header" /><Columns><asp:TemplateField HeaderText="Cargo" SortExpression="strCargo"><ItemTemplate><%# DataBinder.Eval(Container, "DataItem.strCargo")%></ItemTemplate><EditItemTemplate><asp:TextBox ID="txtstrCargo" runat="server" Width="250px" Text='<%# DataBinder.Eval(Container, "DataItem.strCargo")%>'></asp:TextBox><asp:RequiredFieldValidator ID="rfvstrCargo" runat="server" ControlToValidate="txtstrCargo" ErrorMessage="*" ForeColor="Red" SetFocusOnError="true" ValidationGroup="updCargo"></asp:RequiredFieldValidator></EditItemTemplate><FooterTemplate><asp:TextBox ID="txtstrCargo" runat="server" Width="250px"></asp:TextBox><asp:RequiredFieldValidator ID="rfvstrCargo" runat="server" ControlToValidate="txtstrCargo" ErrorMessage="*" ForeColor="Red" SetFocusOnError="true" ValidationGroup="addCargo"></asp:RequiredFieldValidator></FooterTemplate></asp:TemplateField><asp:TemplateField HeaderText="Edit"><ItemTemplate><asp:ImageButton ID="btnEdit" runat="server" CausesValidation="false" CommandName="Edit"
                                    ImageUrl="~/Images/edit.png" />&nbsp;<asp:ImageButton ID="btnDelete" runat="server" CausesValidation="False" CommandName="Delete"
                                    ImageUrl="~/Images/delete.png" CommandArgument='<%# DataBinder.Eval(Container, "DataItem.IdCargo")%>' /></ItemTemplate><EditItemTemplate><asp:ImageButton ID="btnUpdate" runat="server" CausesValidation="True" CommandName="Update" ValidationGroup="updCargo"
                                    ImageUrl="../Images/save.png" CommandArgument='<%# DataBinder.Eval(Container, "DataItem.IdCargo")%>' />&nbsp;<asp:ImageButton ID="btnCancel" runat="server" CausesValidation="false" CommandName="Cancel"
                                            ImageUrl="../Images/cancel.png" /></EditItemTemplate><FooterTemplate><asp:ImageButton ID="btnAdd" runat="server" CausesValidation="false" CommandName="Insert" ValidationGroup="addCargo"
                                    ImageUrl="~/Images/add.png" /></FooterTemplate></asp:TemplateField></Columns></asp:GridView><uc2:wuc_Mensaje ID="wuc_Mensaje1" runat="server" /></div></ContentTemplate></asp:UpdatePanel></asp:Content>

Also I use the following javascript code related to the ModalPopupExtender.

    Sys.WebForms.PageRequestManager.getInstance().add_beginRequest(beginReq);
    Sys.WebForms.PageRequestManager.getInstance().add_endRequest(endReq);
    function beginReq(sender, args) {
        // muestra el popup     $find(ModalProgress).show();
    }
    function endReq(sender, args) {
        //  esconde el popup     $find(ModalProgress).hide();
    }

When I run the website locally, the events of the button is functioning without problem and execute the statements are scheduled.

The problem arises when public agencies in Windows Azure. The events of the lie buttons do not work. For example, the GridView's ImageButton to insert or edit a line no longer work, just nothing happens.

I tried removing the ModalPopupExtender code and associated JavaScript and the page starts to work fine.

The portal was developed in Visual Studio 2012, WebForm, AjaxControlToolkit 4.5.7.1005. And the reference in the propietie "Copy Local" is True.

Some idea. thanks