Changing backup battery, opening Virus Polar Ti1

  • Hi people, I would like to know how to open my Virus Polar Ti1 to change my dead backup battery.
    Does anyone knows a video/pictures tutorial? I tried to unscrew the 4 back screws and the 6 bottom external screws but there is something still blocking the opening of the whole machine and I'm afraid to break something... I guess that the other screws in the bottom side hold the keyboard and wooden parts, but I wouldn't unscrew unneeded screws for my purpose. The two big pieces of metal in the sides seem almost to come away but they seem to be still locked from something inside..
    I hope that somebody can help my.
    Thank you!