Didn't find much in that thread, but I did just find this blog post which may be useful.
http://d.hatena.ne.jp/blaucollier/20090410/1239320282
It says that you may have to clear Innocent Girl completely (I'm guessing with Vivienne's personality fully upgraded) and also Magashi Eradication (completely, including the escape from the facility), then redo the final chapter. I don't know. I'm still pretty confused about it since there are so many conflicting stories and ideas about how to really do it.
Oh, and where I thought the JP wiki had set up a section for this new route, I was mistaken. That was just the Lumia route. >_< However, they now have an empty section ready, so hopefully details will be added to it in the coming days.