Hi wstmann Welcome to the forums
The issue you mention has something to do with the actual 2wire which would be better discribed as the POS and not your server. Now I am not an expert in configuring the 2wire devices but I do know from reading through the forums that they can be difficult to configure which really makes them a PITA not really a POS. Sorry for the reuse of the terms you have already used.
Here are a couple of links to help you get started. The 2nd link is actually mentioned by Yakuza in the first link:
viewtopic.php?f=7&t=2449&hilit=atthttp://support.2wire.com/?page=view&article=21If you use the Site Search and just enter 2wire for the search you will find several forum posts about 2wire devices that may also shed some light on the difficulty others had with them and what if anything they did to correct the problem at hand.
Also you can run multiple servers from 1 internet connection but you will have to do some manipulation with port forwarding to get them to work. The primary port to play with is 443 and if you can forward external ports to internal then you can leave one server using 443 exclusively and set the other to use say 444 to 443. If your familar with iis you can change the default ports in there but its much simpler to use the router if at all possible.
One thing you will need to know about running multiple servers on your network for remote access is that depending on how you manipulate the ports it will have some effect on the HP Softwares Websites if your running v3.x. If you like those websites you may want to leave your EX470 running the default websites. Editing iis settings helps abit but does not correct fully how they function which is something I could never figure out. Anyway I am running WHS v1 OEM on a HP ProLiant and WHS2011 on a test server. My WHS v1 server is my primary server and I use it as the front door to everything to make connections to my WHS2011 server easier to get to for those who I share my servers with. This is done with whiist an old Add-In to help me create the links on WHS v1.
Hope you get your 2wire functional and hope the added info I posted will help guide you to setting up and working with 2 Servers and remote access from a single internet connection.