A voucher code results in a 0 value. How do we process it?

[Fins]

We have added a voucher code to the site that gives a monetary discount. Sometimes this discount can result in a 0 total which is acceptable to us and we want to process the order. However, it’s not acceptable to PrestaShop as no payment gateway options show and when the “I confirm my order” button is activated the spinning icon appears on the grey transparent boxes and the system hangs. We are using PS v1.4.8.2.

Is there a way to process a 0 value order? I have thought of enabling either COD or Check to see if that would be a workaround, but these would then become available for all orders and we don’t want that. Is there a 0 value payment module that could be used or another solution?