Beat her once in a dance tournament.

In the mission mode, capture all the green area near the middle left (where you start). Travel to the top of the green area and capture some of the land above (note that you don't capture Hawaji right away). Go to the top of all the land you captured. Now, travel to Hawaji. On the way, you should be offered a few songs, backrounds or even a Back-up dancer! Continue this process to get all the stuff through each country.

Submitted by nslaney