Hello,
You have to create another pack and use the "coupon generator" instead of the "random generator".
Thus, instead of just creating a random serial (which can be used with the "Product Add" plugin) ; you can create an HikaShop coupon, a copy of a pre-configured coupon, with the discount and restrictions that you want (x% on a specific product).
The serial won't have any "usage" in HikaSerial but the HikaShop coupon, with the same content as the serial, would be useful during the HikaShop checkout process.
Regards,
Jerome - Obsidev.com
HikaMarket & HikaSerial developer / HikaShop core dev team.
Also helping the HikaShop support team when having some time or couldn't sleep.
By the way, do not send me private message, use the "contact us" form instead.