At the title screen, select the Convert menu. Selecting save data from .hack//Infection, Mutation or Outbreak will give you an email from BlackRose that was sent to Kite after Quarantine. Selecting .hack//Quarantine save data will give you the previous email, and an email from Hokuto(.hack//AI Buster) sent to Rena(.hack//Legend of the Twilight Bracelet). However, in the Japanese release the Hokuto/Rena email is gained from .hack//Fragment save data.