NOTR Thieve's Guild - How do I trigger it?

I played Gothic II when it first came out, bought Night of the Raven addon; but never got around to playing it. Until now. I want to get into the thieve's hideout but can't trigger the guy behind the fish seller.
I did not turn in Rengaru when he stole gold from the merchant, I did the Nagur delivery job. I got the "stuffed" fish from the bandits in the cave near the farm.
Now what? I looked inside the fish and all that was inside was a wanted poster of me. I took it to the fish seller and nothing happens. In Gothic II, after doing this, a meeting of guy behind the fish seller is set up and the next thing you know, you're swimming for the thieves' hideout.
How do I trigger the thieves' hideout?

My mistake, I kept looking at the wrong message. I mistook the Wanted Poster for the real message inside the fish. After reading the correct message; I am now on my way to the Thieves Hideout

Ah, the old mistake.

Nice to see you, Max!