There's no need to have downloaded the stuff in uTorrent to fake, unless of course you want the actual files. And it's better if you use a client mR can emulate (like Azureus or BitTornado) to download them, to avoid drawing attention by using different clients to leech and "seed".
To add a torrent to mRatio, go to File -> Add Torrent. Browse to the folder you have the .torrent on, and select it. In the "Add..." window, choose your desired client emulation in the left, and the fake speeds:
http://www.sb-innovation.de/attachme...achmentid=3363
When done, click Add at the bottom, then right-click your newly added torrent in the main window, and click Start. It should now be up, running and faking.