Update currency when choose COD

[soonflex]

Hi,

 

I would like restrict my clients to pay in specified currency when they choose cashondelivery payment method.

 

I added to cashondelivery.php:

global $cookie;
$cookie->id_currency = 1;

and it change currency, but I must reload page to update cart currency.

So I need to update cart, but when I add:

global $cart;

$cart->id_currency = 1;
$cart->update();

It does not work.