I have been looking at that recently. The quick answer is like this:
request (UpdateLocation, "My Room")
http://quest5.net/wiki/RequestThis is done in OnEnterRoom, and I wonder if it would be useful for OnEnterRoom to call a function to get the string to be displayed. Authors can then write their own function to display what the want on the status bar (for example, a list of available exits, or nothing at all).