ok well i tried a jap save file from hgss on english rom and it works all you have to do is make sure that .nds file is the same as the .sav file
just to add on i got jap save from gamefaqs and first tried it on jap rom un translated and it was all in japanese including pokemon names. than i changed the .sav file to match my english rom and put it on my cyclo and it worked everything was in english including the pokemon