[Q] Backing up to external SD card for SafeStrap V3

I'm having the worst time trying to find out how to friggin' backup my phone to my external sd card. For some reason, I can do it to my internal storage, but have no way of getting it backed up to my external SD card. I can see the option to select it, but I can't actually select it. I think I have to create a folder on my external SD card for the root but I just can't figure it out. Does the whole entire SafeStrap file need to be copied over to my SD cars as well with a repeat process of installing it the same way in which I did for the internal storage too?

I have not, as I assumed that while that might be an option, that if I cannot select the external storage option then something is wrong with SafeStrap. If all I have to do is manually copy it over to my external SD card, and with that done Safestrap can still function OK, then that is what I can do. I thought there was something smaller I might have been missing, so I wanted to make sure it was done accurately. Thanks for the input!

EDIT: My real worry with this, is that if I cannot select external SD storage, then how will I select the files I need to install when flashing ROM? I don't have enough space on my internal storage for the files, and would have to put them onto my external SD card, but if I can't select it then I have no clue how I'll be able to flash the ROM.

Well, I got the ROM to work. Since my internal storage is only 5 GB, I couldn't leave both the backup file and the ROM zip files on the same storage device, so I moved the backup manually to my external SD and left the ROM.zip on my internal. I flashed them, got the ROM to work but when I opened it up and booted, as I expected, the phone is like new (nothing installed like I originally had it). Well, I can't restore the backup since it is on my external SD card and since I can't still select that option under SafeStrap, I'm kind of in a pickle here. As well, I my computer couldn't recognize my phone either when on the new CM10 ROM. I'm just going ROM this weekend. If any of you have any clue how to get my computer to recognize my phone when booted on the CM10 ROM, or know how to get SafeStrap to allow me to select my external SD card for storage etc I would much appreciate it!!