For your question in Shoutbox:
Using "Ultra ISO" you can add anything you want in that ISO.
All you have to do is, Open that ISO using Ultra ISO, add those files you want to add, and save that ISO (AGAIN) separately. and the next time whn you will open that ISO to burn it on DVD, all you will have to do is click on that option stating "Burn a CD/DVD Image"
.... and NO. It won't affect the BOOT sector at all.