Adding Payment Surcharge To Session

hi i am try build an addon i have to add an payment surcharge .

i try adding following codes checkout.pre

$_SESSION[‘cart’][‘payment_surcharge’] = 50;

$_SESSION[‘cart’][‘payment_surcharge_title’] = “surcharge”;

fn_save_cart_content($_SESSION[‘cart’], $_SESSION[‘auth’]);

fn_calculate_cart_content($_SESSION[‘cart’], $_SESSION[‘auth’], ‘S’, true, ‘F’, true);

and i iam getting values in array with print_r ($_SESSION[‘cart’]);

but order total not chancing. what i can i do ?

Why you do not use default Surcharge feature?

i have an private payment methods and have installment. i am drt on change box recalcutae order total

Suggest you build your payment method to work with cs-cart as all other payment methods. You can do whatever you want in it. It's just the admin and configuraiton details that are separate. You'd then be able to use the payment surcharge related to your payment method and have it handle it for you.

Look at other payment methods. Some are pretty simple examples.

mate surcharge changing on payment step if user change selectbox