Are you using the time when you start from the DS menu, like you should be, or something else (like the time when you press Continue)? Are you leaving all your buttons alone until the Gamefreak logo?
I can go back on the thread if you would like but just thought this may be easier. I am doing the same thing I did for Black, it just isn't working. I use the time from the DS Menu, and I do wait for the gamefreak logo (i am supposed to wait for it to show up then disappear again before pressing anything, correct? as that is what i am doing).