Provided that if you have Visual Works of Anubis, Pop the special demo disc into your PS2. In the main title, there is an option of 3 : New Game, Save, and Options. Play through the demo, and after you clear the demo, you'll be brought back to the title screen. Save it. Once saved, pop in your Original ZOE2 game again, and all Ex-missions and VS mech will be unlocked.

Notel: this code only applies to the Japanese version.