you can't get in diamond but you can get one for my dick
action replay or event
Probably.
Mystery Gift or using Action Replay
first you must have 666666666666 darkrais than you can talk to the man in ##### and jubilife town than you get the members card
You have to have either an action replay or an event.
get the members card and go into the house with the locked door
no you can only get it by mystery gft
You had to have a Wi-Fi connection when there was the event, or us an AR code but, i can't remember it.
You can get the member card in diamond and pearl but the event for it in platinum is august 3rd to September 13th (you have to have wi-fi connection to do this)
you get it through Nintendo event or mystery gift on Pokemon pearl platinum or diamond
You need a members pass/card to get into the hotel in the same town, then you'll be at the island after a bit of dialogue (You can only get a members pass/card from Pokemon events or AR).
first you must mave a members card with is only avalible at a Nintendo event by via WI-FI