Sorry about the double post but here's something from wikipedia about shun goku satsu:
Storywise, during the Shun Goku Satsu the martial artist drags their victim to the Netherealm (Hell) where their bodies are both burned and simultaneously attacked by demons. The ferocity with which these demons attack depends on the amount of negative karma an individual has accrued over their lifetime.
It doesn't matter if he has a soul or not, he's just gone.