You need to add an additional host name to the Integrated Web Server. Check out: http://inedo.com/support/kb/1014

From a licensing standpoint, a "user" is simply someone who has access to and uses the functionality of BuildMaster: whether that's designing deploying plans, kicking off new builds, or analyzing data. That being said, BuildMaster is designed (and priced) to be used by the entire development organization. The reason is that we believe everyone involved in development should be involved in (or atleast aware of) the process, not just those on a Change Management team. While you can buy as few licenses as you'd like, there's a lot less value when only a small group has access

See: http://blog.inedo.com/2011/10/04/changing-buildmasters-url-with-the-integrated-web-server/