Images that include the Hypertext Transfer Protocol Daemon (HTTPD) also include an ISAPI extension for basic server administration allowing you to restart the server, manage the virtual directories as well as some server security features. The extension is mapped to http://{device IP}/Admin and is used through any browser. The extension itself is found at \windows\httpdadm.dll.
ADS Builds do not have any user information set, including Admin users, so you cannot navigate to this page without first setting up at least one user (you will get an authentication dialog but will no be able to get past it). In order to set up an Admin user, add the following key to ADSLOAD.REG:
This sets the Administrator username. You can add multiple usernames by separating names with a semicolon.
Once you have set the username, boot your system then set a device password through the Password Control Panel applet. Once you have both a username and password set you can log in to the Admin page.