How to disable clipboard from remote desktop server to local PC

Hi folks,

We have a server running MS Server 2003 and connect to it via Remote Desktop from PCs running Windows XP or Vista.
Right now, text can be copied from the server and pasted into documents in the local clients.
I need to disable this "clipboard sharing" option, so no text can be copied from the server to the clients.
How do I do that?? where are the settings in the server??
thanks!