Having some issues getting my modded save files back onto the USB flash drive. Any help would be great.

First and foremost: I'm new to modding save files (and it seems quite intriguing when you want to add a bit of... fun... to the game.

I'm using Gibbed's Borderlands 2 Save Editor in hopes to create a super character with ridiculous weapons (I've already conquered the game a few times... I just want to help some friends at this point). What I do so far...

• Extract save file from USB flash drive using Modio or Horizon.
• Open save file in Gibbed's.
• Tweak the character file how I want and create a couple new weapons/items.
• Save the file and close Gibbed's.
• Open Modio/Horizon and attempt to "inject" the save file back into the USB flash drive.

When trying to open it in Horizon, I get a message that says (letter for letter, space for space):

Invalid signature type detected for the loaded package. Halting reading. Please make sure the file is a valid XBox 360 XContent Package ('LIVE'. 'PIRS'. 'CON ')

And the error from Modio:

There was an error attempting to open your save, Invalid XBox Package.

Thanks in advance.