you can actually do all of what you want. you can 'backup' a save instead of copying it. also for getting other protected saves, there is a program that you can use on someone elses saves to change it to one of your own.
lucky for you i found it in my pc without to much hassle, its called PS3 save resigner 2.0.6, as i recall you will want your PSN account name or something, and then edit some of the saves encrypted data using the program, to make it your own. its really easy to use.
i recommend using it for games with unlockable modes and stuff, i used it for star ocean the last hope on PS3, as that has protected saves, and requires you to beat the game 3 or 4 times to unlock the max difficulty setting lol. also useful for tales of games, and other such games with unlocks like resident evil with the unlocking of merc mode maps, or any game with NG+ only content that your allowed to start a 'fresh NG+' file,. such as the guided fate paradox (a PS3 rougelike)
hope i helped, if you have any troubles, leave me a message and ill get back to you.
