So I'm playing Pokemon white I have my own "Liberty Pass" I talked to the captain in the pier on the most left but he doesn't take me to the liberty garden and Sorry I'm bad at english :C
Just getting the Liberty Pass isn't enough. You have to also have the Wonder Card that enables the retrieval of the Liberty Pass from the courier inside the PokeCenter. Without the Wonder Card obtained via Wi-Fi, the Liberty Pass will not function.
Source : GameFAQ Forum