For those that haven't yet found it, the Signum doujin has been translated.
http://g.e-hentai.org/g/324514/1d7f9aaa8c/
Appears Hayate went a little evil from the Book of Darkness, or the Book of Darkness take over. Your standard tentacle sexing brainwashing, with a little yuri thrown in. Now all we need to do is wait for part two with Fate.
Here's some bonus art from the artist's pixiv page.