Virtua Striker F.C. Sega team
At the team selection screen, highlight the following teams in order and press Start over each one before moving to the next: Spain, England, Germany, Argentina. You can now select F.C. Sega as a team.
Big heads mode
When the commentator announces the competing teams, press Up, Down, Left, Right, [Long Pass]. Note: Both players must enter the code if playing in Two Player mode.
The image featured at the top of this post is ©The Legend of Heroes: Trails of Cold Steel III key art.