Don't know if you're still looking for this.

Edit GetOnlineUsers sproc.
replace Users.UserName by Users.FirstName

That should do it.

Well, I tryed it, but it gave me an error.

---------
CREATE PROCEDURE dbo.GetOnlineUsers

@PortalID int

AS

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

to ----------------------

CREATE PROCEDURE dbo.GetOnlineUsers

@PortalID int

AS

select UsersOnline.UserID,
       Users.FirstName
from   UsersOnline, Users
where  UsersOnline.PortalID = @PortalID
and    UsersOnline.UserID = Users.UserID
GO