SWART2/GWART2 Help! (Port Forwarding Setup Issue)

[Rufus]

As we all know, port forwarding is usually difficult. However, that's not usually a problem... I've spent hours fixing port issues before... but this isn't a port issue, unfortunately, and it's one that's been bugging me for months!

Now, in some cases of port forwarding, you need to forward sometimes very large ranges of ports.
This is the case in such scenarios as Valve's Half Life 2.
Unfortunately for me, when I tried forwarding the ports for Half Life 2, I suddenly became -very- aware that there was something missing.
(Here's the portforward.com's tutorial on how to forward the required ports: http://www.portforward.com/english/rout ... _Steam.htm - As you may notice, my issue is actually shown there, but it's easy to miss.)
As you will see from both the portforward.com article, and my attached screenshot of my forwarding setup page, the "Port Map End" text box is missing.
So far I've resorted to trying to add each port manually, but there are far too many to do so, and now it's full.
I've been fruitlessly searching for a way to put a range into that box for months. (Not just with Half Life, but other things before it.)
I've even tried putting the range into that one box, such as:
Port Start: 100
Port End: 105
Port Map: 100-105 (Also tried 100,105 and 100;105)
I'm all out of ideas here...
Is there anything I can do to get it to work?

[biro]

To forward a range of ports "Port Map" should be the same as "Port Start"

eg
Port start: 1
Port end: 10
Port Map: 1

would forward WAN port 1 to LAN port 1, port 2 to 2 ........ port 10 to 10

[Rufus]

Ah, so the one I hadn't expected to work at the bottom must be...

Thank you, this should help me a lot!