ZkinandBonez said:

Hal 9000 said:

Obi-Wan said he trained Vader in ANH, not Luke's father.

Right, it's so hard to think of them as two different people at this point. But you're right, he only refers to Vader as his pupil and just says that he fought alongside Luke's father in the Clone Wars.

This probably isn't worth much, but I looked through my re-prints of the Marvel SW comics that were published between 1977-1980, and there's an Annual issue that mentions Obi-Wan's two students; Skywalker and Vader.
I'm wondering if the comic writer simply assumed that they were both Obi-Wan's pupils during the Clone Wars, but it is possible that he had that information from Lucas/Lucasfilm.

Of course these comics are known for some amusing plot details that quickly became non-canon as the movies were released, but even their weird interpretation of Jabba the Hutt (or "Hut" as they called him) were still based on notes from Lucasfilm. I remeber reading somewhere that the second appearance of Jabba was commissioned by Lucasfilm since they intended to mention him again in ESB. Of course three years later they decided to show him looking completely different anyway.