force the same address for both shipping and billing

gistfile1.js

<script type="text/javascript">
$('#CheckoutStepShippingAddress').remove();
$(document).ready(function(){
$('.ExpressCheckoutContent').ajaxSuccess(function(){
    $('#BillingAddressTypeNew').parent().hide();
    $('#ship_to_billing_existing').attr('checked','checked');
    $('#ship_to_billing_existing').parent().hide();
    $('#ship_to_billing_new').attr('checked','checked');
    $('#ship_to_billing_new').parent().hide();
    $('.billingButton').attr('value','Proceed');
    });
});
</script>