I m trying to change the total price depending on payment method .
I’ve made it with jquery in cart page
but i cant do anything with php im updating
$_SESSION['wpsc_cart->total_price'] but when trasfering the price on database and sending the email total price doesnt changes ….
My jquery code is below

var pric= $(‘.wpsc_totals #checkout_total .pricedisplay’).html();
var priceAsFloat = function (pric) {
return parseFloat(pric.replace(/\./g, ”).replace(/,/g,’.').replace(/[^\d\.]/g,”), 10);
}
var pri= priceAsFloat(pric);
var newprice= pri +4.00;
$(document).ready(function(){
test=$(“input[value$='wpsc_merchant_testmode']:radio:checked”).val();
if( test==”wpsc_merchant_testmode”){
$(“#checkout_total .pricedisplay”).html(newprice);
}
else{
$(“#checkout_total .pricedisplay”).html(pric);
}
$(“input[name$='custom_gateway']“).click(function() {
test=$(“input[value$='wpsc_merchant_testmode']:radio:checked”).val();
if( test==”wpsc_merchant_testmode”){
$(“#checkout_total .pricedisplay”).html(newprice);
}
else{
$(“#checkout_total .pricedisplay”).html(pric);
}
});
});

and php code that i have made but not working is

$total = $wpsc_cart->calculate_subtotal();
$total += $wpsc_cart->calculate_total_shipping();
$newtotal= $total + 4;
….
total_price’]=$newtotal;?>

I want to do that thing because my delivery services asks for 4 aditional euros if they get paid when the product delievered to the customer:(
Plz give some help i cant understand how that works:)