It has already been released but it seems it is nowhere to be found.
Thanks !
EDIT 1 : Found this http://www.nicovideo.jp/watch/sm30139989 but they are only previews I guess.
EDIT 2 : Found it http://www.bilibili.com/video/av7583797/index_1.html . Feel free to rip it…
Here the actual soundtrack. Enjoy.