It's not really a sequal to the James Cameron one it's a mockbuster of it.
Then what's with the II in it? Why not just call it Titantic?
I don't why they did it. Perhaps they called it that to cause confusion? The James Cameron one is being re-released in 2012.
Because Asylum likes to ride the coattails of far superior, much more successful movies. Think about it: Titanic (was) the highest grossing movie of all time. If they claimed to have done a sequel to it, many people would blindly rent it, thinking it to be an actual sequel. It's actually kind of ingenious, albeit dishonest but when has dishonesty ever stopped them before?