General questions and discussions.

I was bored, so I decided to play through a Heroes campaign. I might be missing something, but in the "In Search of the Horn" mission from the "Storm of Seas" campaign, Bidli and Dargem need the Captain's Hat to get to the portal through the ghosts. I have the hat, but it's only on the hero's inventory, not in these underwater corridors. How do I get it there?