I can't get why people here really think this scene was post-KHII. All of the scene in the trailer shows things that happened between the games, why would that scene (which was not even the last scene of the trailer) shows something of the future, while none of the other scene relly does?
That's actually not true...there are scenes which can't be set in the timeline between KH: BBS and KH: Coded, like Xehanort on the beach of DI turning around changing into Ansem SoD, Xemnas and then Master Xehanort, Sora vanishing from the Papou tree and Ven's body disappearing from the chamber of waking.
While these scenes may be only symbolical in meaning for something they are new...as well as the one of Riku stalking Roxas and Xion, DiZ actually inserting the data into the sleeping Sora and of course also the Kairi scene.
It can't be said for sure that the Kairi scene is after Coded or during KH II, but the possibility that Kairi will finally do something besides her current two main actions (sitting on the Islands twiddling thumbs or getting kidnapped) is there and has to be taken into consideration.