Missed out the Japanese DLC? No problem!

1: Download SKFU Proxy:

http://wololo.net/downloads/index.php/download/1301

2: Change your 3DS's proxy settings to match those in SKFU Proxy

3: Download the following (Save Page As):

EU: http://puu.sh/jn7oY/913211e784.httprls

US: http://puu.sh/jn7pX/f3cee57ffa.httprls

4: Import the files into SKFU's HTTP(S) Rules

5: Connect to download the DLC as you usually would

You should be able to download:

All event quests, the most recent batch of quests included a bunch of 10th Anniversary equipment (see: http://puu.sh/knou9/84fafa1410.jpg)

All challenge quests

Enjoy!