I have an MVP130 set up behind a firewall on a VPN using Comcast as the ISP. They block port 80. How can I change the port to another port such as 8080 so I can access the unit over the Internet?

Using an alternate port number would need to be done with the router setup. For example, on our NAT routers you could map the external IP's port 8080 to the internal voip IP's port 80.