NAT Loopback on Zyxel EMG2926

I would like to enable NAT Loopback on my Videotron EMG2926 router. I've been through the manuals and cannot find the option. I use No-IP as my DDNS service. The issue is from outside my local LAN I am able to reach the service I need with MYNAME.ddns.net:port-number. When I try the same MYNAME.ddns.net:portnumber from inside my private LAN, I get service not available or not responding. It seems the ZYXEL is blocking the request. If I use the internal IP of the server like 192.168.0.123:port-number it works fine. I've done some research and believe NAT Loopback(aka Hairpinning, Reflection) is not enabled in the router. This is a pain as I will need 2 links on my laptop, one for remote access and one for local access. Does anyone know how to enable this? My last chat with Videotron led me to the manual on page 106..... Not very helpful. I pressed further and was told I would have to pay for advanced support.... Oh well....

Thanks for your help everyone.

Bob.Barbagallo@Gmail.com