I just added this anime to my Sonarr under it’s English name and told it to download if Horriblesubs exists in the file name and it’s found the releases. Which is to be expected.
However, I am guessing what you want is when Sonarr names the files you want it to name them as the Japanese release and not the English translated show name? I don’t think it’s going to be capable of that since it names it as what the show is showed in the list.