While browsing for information in the past about securing a TS server I came across a website that had 2 excellent hacks for TServices, unfortunately now I am unable to locate the website again.
The first hack changed the function of the X in the upper right hand corner when pressed to show a pop-up dialogue box that said you must select start -> logoff in order to end your session.
The second hack changed a registry setting on both the TServer and clients connecting to the server. The change was to the TS ID number possibly? I can not clearly remember I only know the number that was changed (not the port) had to match on both the server and pc this greatly helped in preventing unauthorized access to the TServer since you would have to guess the correct number combination in order to start a session.