That's because Sony's not publishing the game in the US, instead handing off the rights to D3 Publisher.
The game will release on PS3 this summer, complete with the new game and the "remastered" version of the original (as in Japan). So, just to clarify, you'll get both White Knight Chronicles games when you buy the sequel. Unlike the Japanese version though, you won't have to beat the original WKC before you play the sequel. You can play them in whichever order you like.