Attention! Make sure that you have also already set the firewall to the new port before you apply the settings below.
For customers who do not want the Remote Desktop to listen to default port 3389: http://support.microsoft.com/kb/306759
Start the Registry Editor
Click the following registry subkey:
Choose Modify in the context menu and select Decimal.
Enter the new port number and click OK.
Close the Registry Editor.
The change only goes into effect once the server is restarted. After the restart, the RDP is only accessible via the new port number. Please also notify the support desk if you will be using an alternative port. The support desk can then log in for support without having to ask additional questions.