You can't edit the item table in the savegame right now, not until the file compression is figured out.
Everything after the header of the file is compressed (LZ ?). I think the original Story of Seasons used some LZ compression,
at least that's what I remember from looking through the sourcecode of the savegame editor for that game. You could try to ask RainThunder for help, that's the user who wrote the savegame editor for the original Story Of Seasons
The new game uses a new save format and I am unable to find the compression header so I can't figure out which compression algorithm it uses. I have even looked into the game's code, and am getting closer, but still haven't quite figured it out.. I'm also pretty new to REing from assembly.
i really want to play this game clean and fair. But so far, my hard work has gave me a S rank by-product level chicken, which make my chicken only lay golden eggs. And then that stupid egg couldnt be use in cooking... Damn, now i'm looking for a way to reduce that S rank...
I don't know if it's worth to check, but maybe the .cec file extracted with the saveX.bin files (when extracted with jksv) contains that data? :S