I have bad news. All my research on Pokeshifting, which amounted to finding very little info, failed big time because the Pokeshifting app may be for DSi only and this, of course, is region locked. So I bought a Japanese Diamond game for nothing and I beat my game for nothing too, because now I can't RNG my Reshiram on my retail game. :-( Edit: I only found out after finally finding the building for pokeshifting. And finally, I see letters in plain English on the game -- DSi/DSiLL. I am still trying to figure this out without the help of any guides, so I'm still hoping I'm wrong and that I'll find a way to pokeshift using DS Lites.
I'm definitely going to restart this game once the RNG is cracked.