If you cannot talk to him make sure you have completed all four quest lines. A commonly missed quest is Scribblings on the Wall
If you have a Mark of Manaar in your shared bank (from completing the quest line with another toon) you will automatically get your update to this quest. You must place a Mark of Manaar in your inventory.
On Feb 12, 2013, I was able to complete this quest with -5K faction with City of Paineel. I did have to remove the Mark of Manaar from the shared bank and place it in my inventory to get the quest update, but it was not in my inventory when I turned in the quest.
The Mark of Manaar may be in your currency window, if /finditem doesn't actually find anything.
You must get some sort of token to prove your trust.