In an hour from now when the maintenance is over… from noon Japan time, you will be able to download the update and then purchase the Costume Set Vol.1 from the PlayStation Store for 600 yen.
As usual, you will be forced to automatically update your client when you log online so that everyone can see the new costumes when you use them.
Update [08052901]:
Hope they add some new items to collect for lobby parts… it is hard just collecting first and second place prizes when there is not that many tournaments.