Is there a way to change the port the web management page uses to something other than 80?
If not, how can I access the web interface remotely if there is a webserver in the DMZ?
use port forwarding and use a random port such as 8080 or 8000 for the outside port and forward it to port 80 of the IP Address of the ap.
so in order to access it you would use the Public IP of the router with port 8080 for example. http://PublicIP:8080
which would in turn forward traffic coming into port 8080 to be sent to port 80 of the AP