Trouble shooting forwarding/ddns issues...

I would really appreciate some help getting my head around port forwarding and ddns and how to tell if its working or not, or if I've not done something right.

I have a WHS2011 server with a Microsoft live domain (myname.homeserver.com). Its part of the WHS setup, not something that runs anywhere else.

I have a website on that server which I can access remotely via myname.homeserver.com:port1.

When I was using Unotelly I used the same domain name to keep my IP updated with them and that worked, so I dont think the Live domain is WHS specific.

Now I have replicated the website on a NAS which I can access internally. I have put a new forwarding rule in my HG659b.

So I have two forwarding rules now, two ports, two different internal devices, both with static IPs.

Rule 1 : WHSWEB : PORT1 : WHSIP10

Rule 2 : NASWEB : PORT2 : NASIP11

(in the HG659b the devices dont appear as IP addresess but as MAC addresses)

But I cant the NAS website remotely using myname.homeserver.com:port2.

I'll need to get an alternative DDNS service at some point as the WHS server is being retired, but not until I can get remote access to the NAS working.

I have tried substituting myname.homeserver.com with my.external.IP:port2 but still no joy, so that removes the Live domain from the equation right?

The web response is "This site can't be reached. my.external.IP took too long to respond."

I dont know if this means the site just could not be found, or it was found but was too slow.

Is there anything I have overlooked?