I am also interested in knowing if this is possible using acsx file editing or other options.

I am running DNN 4.5.3

I got it using Display name by altering the "GetOnlineUsers" stored procedure.  I've pasted the SQL below.  Tested for DNN 4.6.0 only.  Use at your own risk.

For a demo of what it looks like, see helpdesk software

Best regards,

Rod.

---

ALTER PROCEDURE [dbo].[GetOnlineUsers]


@PortalID int

AS

select UsersOnline.UserID,
       Users.DisplayName As UserName
from   UsersOnline, Users
where  UsersOnline.PortalID = @PortalID
and    UsersOnline.UserID = Users.UserID