Well, I can get the external camera to work when I choose "Normal", but I have to go back into Gameplay Settings ~after~ I do the Career start. I start the career, name, port, etc., go to the boat screen, get the crew and any changes I want to make that are available for the boat, "Save", back out to the Main Menu, Options, Gameplay Settings, Save (or whatever they call it there), then Load Game and start the actual Career. Extra step, but it's almost a necessity to have the camera for "testing" documentation. I don't think the camera is available on the higher settings though. RR or cdrsubron7 could probably say for certain...
Edit: and look at that, there is your answer, before I can even get finished typing...