I've been under the impression that Luke did burn Vader/Anakin's physical body as we didn't see him pass on or "disappear" into the force as Obi-Wan and Yoda did. And, if Hasbro were to do it right, Vader shouldn't include his right hand since he lost that down the reactor shaft courtesy of Luke.
I don't have a link, but to clear it up for you, if you go to Wookiepedia and search Darth Vader, it says that what was left of his organic body dematerialized. Yeah, we don't see it happen, but he passed on like Yoda and Obi-Wan did (makes you wonder why Qui-Gon didn't). So all Luke is burning is his armor.