It seems that the DLC was postponed in Japan. Also you can get the costumes on the official site somehow(If you figure out how then tell me).
From Software announced they were delaying their 3D Dot Game Heroes holiday update on Christmas Eve, a day before the patch was scheduled to go online.
Every dot adventurer gets a free feature filled patch that adds a loading screen viewer, an optional hard disk install, and access to DLC to 3D Dot Game Heroes. Fork over 250 yen ($2.75) for ten extra block defense stages and ten character edit data files. A second DLC pack with more character edit data goes for 100 yen ($1.09).
The update and downloadable content packs have been rescheduled for January 2010. I wouldn’t be too psyched about the DLC because many of those character models including the “President” from Metal Wolf Chaos, Ayame from Tenchu, and Dragon can be downloaded for free directly from the 3D Dot Game Heroes site. From Software released a bunch of edit data in November when 3D Dot Game Heroes launched in Japan. All you need is a USB drive to transfer the files from a PC to PS3.
http://www.siliconera.com/2009/12/29/3d-dot-game-heroes-update-and-dlc-delayed/
Edit: Give me a sec and I will upload the photos to my photobucket account