Need a payment for ZERO total amount (coupon)

-- HikaShop version -- : 2.6.0
-- Joomla version -- : 3.4.3
-- PHP version -- : 5.5.23

Hi
I have coupons in my shop and because of that it is possible that the total price of an order is zero.
I need to display a message in the checkout step "payment", so I trying to setup a "payment" for zero total amount orders.

But, I can't catch them with a payment method.

I've tried limit maximum amount 0
I've tried limit minimum amount 0.1

But, the payment method is ignored.
I've tried to use the collectondelivery.

It is possible it is ignored because there is nothing to pay?
Is there a solution for this then?

Hello,
but this would affect all orders and not all my orders are zero.

I need a way to select a payment for the zero amount orders
or
can i use an if statement in the file "payment" of the view "checkout? If so, please show an example