Larian Studios Forums Divine Divinity (English) General Trying to get inside Stormfist via sewers

I was thrown out of Stormfist, captured by Iona, escaped via white cat, entered Ars ARcana sewers, reached Versistis Sewers and left so I am under Castle Stormfist. However, cannot open door without key (I have lockpick maxed).
Is there something I missed? Need Help.

You're in Stormfist Castle, but at the wrong entrance.

You must not enter through the torture chamber, but through the treasure room.

Lokk around for another entrance - or become a member of the thieves guild in Verdistis - Rob, the boss, will give you a map where the entrances are marked.

The castle treasure room entrance is in the Rivertown sewers, closer to the poor quarted entrance than Ars Magicana, south of the entrance to the Verdistis sewers. There are a couple doors in the Verdistis sewers which must be opened by levers from the other side.

Ars Magicana Sewers screenshot map