bug report: arx Magister last stand secret room (located x:60;y:0)

[AFAA]

Hi, i had an issue in the game, sebille found the switch button to open the door (on the right side of the door, apart from the 4 switches in the room and the one in the secret roomon the right when entering) but it can't be used, i dont have the button lighted up. I also found the other way to access the room from the room where you kill magister reimond, but i can't use the way either.
If anyone has a solution i would be pretty happy.