ES450 Remote Camera Access

Just installed an ES 450 and I cannot get through the unit from the outside to view cameras.
I opened the necessary port and even set up DMZ for the DVR ip.
I can ping the external ip, but cannot connect to the cameras.
Am I missing some configuration on this unit ?

Is the GX450 in private or public mode
If it is private mode, is the DVR getting a DHCP address from the GX450 or is it statically assigned
Can you ping the LAN IP of the DVR from the GX modem (AceManager -> Admin tab -> Advanced -> Ping)

It will be good to contact your distributer to get a better help…