Not sure about it working as I haven't got a freeview card in my machine as well but I wouldn't of thought it would break any other scanning.
But 1 thing to mention which you didn't do in your steps for setting up is that both setup tv-engine and setup mediaportal svns need to be installed on both machines ie clients and tv server.
What make of dvb-t do you have? have you tested it with 1.2 beta without the svn? What Operating System are you using?
Maybe with some more info some1 else could confirm it working or not.
Rich
Ok I installed the client svn onto the server and the only thing it did is install the client, which has no purpose on the server AFAIK.
Am I missing something?