Here are several reasons I can think of why you can't use VNC through DirecWay:
1.
Private IP Address. DirecWay is acting like a NAT router. If you are like me your host has an IP address that begins with 10.x.x.x. These are by definition unroutable, because they are not unique. A simple test: Can you even Ping your system from another system on the internet? If not, forget about VNC. If you can then you don't have a private IP address, you must have the business account.
2.
Firewall. You have tried many ports on VNC, including "open" ones lke port 80. VNC listens on port 58xx and 59xx where xx is the viewer number (0 is the console). VNC interprets ports under 100 as being added to the basic 5800 and 5900. So if you could open port 5980 and 5880, then you would be able to enter port 80. To really use port 80, you should enter a negative number like -5820. Look here;
http://www.uk.research.att.com/archive/vnc/faq.html#q543.
Router. You have the DW6000, which acts like a NAT router below the DirecWay system. You need to open ports there as well, and perhaps a DMZ as well. This will allow your client to appear to the rest of the network as your DirecWay IP address (even though it has a private IP address to your local network). I don't have the DW6000, so I dont' know if this can be done. I have the DW3000 (DRS) and I know I can't do it.
Brad Houser 
<new to the forum, but I've been around the block a few times>