how to post values from content page in asp.net

[lazybOi]

in my web application I have master page and it has too many content pages and in my content pages I want to post form to other URL. but its accessing the values. When I do the same in simple aspx page without masterpage it works well.\[code\]<%@ Page Title="" Language="C#" MasterPageFile="~/MasterPage.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" %><asp:Content ID="Content1" ContentPlaceHolderID="head" Runat="Server"></asp:Content><asp:Content ID="Content2" ContentPlaceHolderID="ContentPlaceHolder1" Runat="Server"><form id="frmPay"> <div> <!-- Receiver Details --> <input type="hidden" name="merchant_id" id="merchant_id" value="http://stackoverflow.com/questions/12685494/xxgxg" > <input type="hidden" name="merchant_key" id="merchant_key" value="http://stackoverflow.com/questions/12685494/gxgagag" runat="server"> <input type="hidden" name="return_url" id="return_url" value="http://www.widget.co.za/payment_finished" runat="server"> <input type="hidden" name="cancel_url" id="cancel_url" value="http://www.widget.co.za/payment_cancelled" runat="server"> <input type="hidden" name="notify_url" id="notify_url" value="http://www.widget.co.za/payment_notify" runat="server"> <!-- Payer Details --> <input type="hidden" name="name_first" id="name_first" value="http://stackoverflow.com/questions/12685494/Bob" runat="server"> <input type="hidden" name="name_last" id="name_last" value="http://stackoverflow.com/questions/12685494/Smith" runat="server"> <input type="hidden" name="email_address" id="email_address" value="http://stackoverflow.com/questions/12685494/[email protected]" runat="server"> <!-- Transaction Details --> <input type="hidden" name="m_payment_id" id="m_payment_id" value="http://stackoverflow.com/questions/12685494/TRN123456789" runat="server"> <input type="hidden" name="amount" id="amount" value="http://stackoverflow.com/questions/12685494/200.00" runat="server"> <input type="hidden" name="item_name" id="item_name" value="http://stackoverflow.com/questions/12685494/Widget Model 123" runat="server"> <input type="hidden" name="item_description" id="item_description" value="http://stackoverflow.com/questions/12685494/Widget Model 123" runat="server"> <!-- Transaction Options --> <input type="hidden" name="email_confirmation" id="email_confirmation" value="" runat="server"> <!-- Security --> <input type="hidden" name="signature" id="signature" value="" runat="server"> <asp:Button ID="Button1" runat="server" PostBackUrl="https://www.payfast.co.za/eng/process" Text="Button" /> </div> </form></asp:Content>\[/code\]