Originally posted by Alien426
Gorillas! One could even wear Ben's jacket.
Thinking about it, the bikers already have the figure of Gorillas. It could be a little like Planet Of The Apes. You wouldn't see their faces. In the into they would only ride their bikes and then -bam- you see Ben is an ape!
cant imagine that in the opening credits
Vader's wife was very pregnant when she died 19 years ago. All of a sudden a 19 year old who is very strong in the force and has a distinct resembalance to him in his younger days rolls in from Vader's home planet with his old Master Obi-Wan (Who was the ONLY other person preset at the time his wife died. And to boot, the kid's last name is Skywalker.
So in answer to your question, he knew Luke was his son because his name is Darth Vader, and not Darth Retard.
-Forum post on why Vader knew Luke was his son.