After completing some matches, check the Combat Sim Controls in the Armax Combat Arena to read the following e-mail:
At the Combat Simulator Control terminal select Cerberus as the enemy. Choose either no squadmates, James only, or James + Kaidan/Ashley (if the Virmire survivor is alive and available) as your squadmates—no other team members qualify as the specified "Alliance soldier friends"—and complete the combat simulation. Other modifiers are allowed per your choice. Since most challenges are not mutually exclusive, you could conceivably finish other arena challenges at the same time, e.g. Citadel Arena: Medi-Gel Challenge or Citadel Arena: Spin Zone Elite Challenge.
After completing the simulation, check the terminal for the following e-mail: