If you have the retail version the yacht mission is on the bottom right by off Australia; the "scene" releases from what I've heard don't work since the DLCs are checked against your ubi account.
I have it attached to my account.
I need to activate the DLC through the Blacklist service which gives me an unavailable error every time I try to enter the key.
This is happening to many other people,but Steam and Uplay forums blame our machines.We can connect to all other game servers including Uplay servers for their other games. I have gave up on this and will never purchase any other Ubisoft DLC's in the future.