Take the first save on this page, for example:
SAVEGAME LINK
Open the zip file or extract it. The folder you want to send is inside the UDATA folder of the archive.
Connect to your xbox via ftp and go into the e:\UDATA\ folder of the harddrive. Now, transfer the savegame folder and overwrite when it asks (the folder you want to transfer is "4d570019" for this game). You will probably lose your current save. The passward to that save is just "AAAAAAAA".