Modio's STFS repair will do more
damage than repair. (to most games, not all tho) I HIGHLY recommend not using Modio's "rehasher/resigner"
100% of the Time I would recommend 360 Revolution, Horizon and/or CONcept 3.0 (all of which will not corrupt ANY saves)
I speak only through experience and how alot of users all over these communities (especially at GT) who have had problems with save regardless if editors are being used or not -- stopped having issues once they stopped rehashing/resigning with Modio.
To OP, make sure you "replace" the existing
.ess (save that the PC can read ) file within the
.exs (xbox save).
There should not be a .dat file anywhere dealing with Skyrim saves. This could very well be the cause of your problem.
With Horzion you don't need to rename the save (within the CON) to Savegame.ess (if you just go to extract it and hit enter without renaming it, it will keep it's correct format rather then if you rename it will not keep its correct format until you state it when renaming it.
This method is mainly pertaining to the Console Commands that the PC version has which will allow you to mod the PC save which in turn will allow you to be used on your xbox by following this method.
I hope that helps and clears ALOT of things up. :)