I am afraid I havnt anything like that in my Zyxel router.
But I have a SUA/NAT folder with options like "Deafault DMZ server", "Start Port", "End Port", "Server IP Address", and a "Respond to Ping on Internet WAN Port" -button.

I dont understand any of this. Have tried with port 6346 and my Gateway Address as servers, whithout any luck.