You don't say what you're copying but for example, if you rip a movie DVD then you could use Nero Burning ROM. Select DVD in the wizard then choose DVD-Video. After the wizard closes, in the drop down at the center top of Nero Burning ROM select "Image Recorder". Now click on VIDEO_TS folder in the compilation and drag your files from the rip and drop them on the compilation. Burn and it will ask you to name the file. Name it something with an iso extension and it will save to a .iso file.
hi paulo617, I suggest you use the xbox forum as you will get the answer you are looking for. There are experienced folks who have done tons of backup and you can find the best solution that works for you. Good luck in your search.