Seems nobody actually understands what I was trying to say. For the last time, I USED 7-zip to delete files/folders from iso's, because IT JUST DID THE TRICK, NOT BECAUSE I THINK OR CLAIM THAT 7-ZIP IS MEANT TO CREATE/MODIFY/SAVE IMAGE FILES. That's it. I don't need someone's help to read the feature list on the official web page. My initial question was a rather simple one and as soon as someone pointed out that it's not supposed to work the way I used it I gave up on the otherwise foolish idea. I'm done.