You ask how the mind would be a perfect duplicate? I tell you this, Nothing is impossible until it is shown. Catch 22? Exactly my point. You can't prove it wrong until it is. I can tell you it is impossible for me to grow wing and fly away, but then again, just because I don't know the means on how to do it, doesn't mean that the possibility doesn't exist. I ponder the abstract all the time. The "What IFs" are more fun than ever, and its a conversation that will never end. Anything is possible and thus there are limitless possibilities to the original question at hand. Thus I say to you, I don't know how, but you can't ignore the possibility that when teleported the mind is somehow duplicated as well.
Heck who knows maybe if we get the technology that will be a bonus that we never could have imagined.. or perhaps our mind will be DL into a computer, transmitted over the net and put into the new body... Unlimited life assuming the Transmission doesn't decay. Again, yet another idea that can't be proven wrong. It can be shown impossibe at the current time, but not overall.