Disallow to add other products and purchase act generator

[codylt]

Hello,
I have a shop that runs on virtuemart, and we tought about adding coupons for sale. But the problem is, in our country you can't apply VAT for the coupons so now i have these problems :

How to disallow the client, to add coupon if there is other things in the cart? And the way around - how to prevent adding other products, if the only the coupons are in the cart?

Second headache is that i need to generate "purchase act" when people buys coupons (now they get invoices) but i need "invoice" type act, without VAT ONLY for those coupons.

Is it really possible? I wanted to see developers, but there isn't a lot of people who works with joomla/virtuemart here...

[Studio 42]

Hi, you can apply taxes per category. and price per shoppergroups. Perhaps this help ?
About coupon. with awo coupon (PRO) you have more options that virtuemart core coupon.
I can code you a plugin to disallow coupon only in cart.