First: Grab SaveDataFiller and go to de 'user' section and export the save (Y) withID 1646CTR-card (I use .3dz)
Second: Copy the folder located in the SD://filler/user/
Third: Open the savedata tool and search the 00slot00.dat in the folder you have copied
Forth: When you have located the file open it and edit the amount of Diamonds or Poke that you want.
After that save it and re-copy the folder to the SD again.
Fift: Open the SFD now we are goig to re-import the save but before that you need to delete the secure value or your save will be corrupted, for that in the 'User' section locate the ID 1646 and hit (R+Y) to delete the secure value.
After that go to de 'SD' section and import the modified data(A).
Finaly: Open the game and enjoy the Diamonds♦, Poke, whatever you had edited.
This is exactly what I do, but after importing, I must start over again.
Why?
I also tried to save as both in the tool compressed and decompressed to be sure.
I want my not-edited Kyogre back.