I don't find a way to enter the central part of the Gate of the Ancients, the one that has the form of a key.
I have Sifrinni Orb and in The pits i found the buttons that should open the way to the central room, but i don't know I to go there. Is there some other button to push somewhere or a room to discover? (in maps i found a room that i cannot reach)

Thank you for help

I answer to my question. I found the way to the central room.

For anyone who need help here there is a really well made video Walkthrough: https://www.youtube.com/watch?v=ee7ZwlUPynQ&list=PLC3894C6454C91D23&index=1