This being said, and after some time roaming the web, I finally found the YS Seven OST (As far as I can tell, only the Game Rip version was available on these forums).
Disc 1 : http://rapidshare.com/files/319370172/YS7_OST_D1_sonixgvn.rar
Disc 2 : http://rapidshare.com/files/319368795/YS7_OST_D2_sonixgvn.rar
Enjoy 🙂
EDIT : Password is sonixgvn.