While it was never mentioned in M7 as to how Basara got the Fire Valkyrie, it was the UN military who "gave" it to Ray and then to Basara. How else can a civilian get a hold of a top of the line fighter that's modified with speakers? After the war ended the UN realized the potential of song/ culture. Thus Project M(inmei) was in the works. Ray gives Basara the 19. With Basara being Basara he doesn't question why and just does his thing in battle. Those were I guess open experiments to see how far Basara can take it. Eventually it was proven that song can affect the enemy.