MCSA/MCSE Exam 70-290: Managing and Maintaining a Windows Server 2003 Environment says:
Only the Remove Desktop MMC snap=on and the mstsc /console command can be used to connect to the console session of a Terminal Services computer. However, an administrator actually sitting at the server and using the console session can request help by using the Remote Assistance functionality in Terminal Services. It is important to note that for security reasons, a console session cannot be viewed using Remote Control.
I'm sorry, I thought you were just talking about changing the TSAC port, which is possible.
SecurityFocus Microsoft: Changing Terminal Server port in TSAC ActiveX Web Control says:
The way the TSWeb access works is by simply loading an ASP page (CONNECT.ASP) that calls the MSRDP.OCX ActiveX Object. For those of you that want to use the ActiveX control to connect to a different listening port, all you have to do is edit the CONNECT.ASP page, and add the following line before the MsTsc.Connect method:
- - where is X is the custom port your TS is listening on (in decimal). When the ActiveX control attempts to connect to the TS, it will now use this port.