I'm stuck on this one as well. It's the only mission I have left besides the free missions that doesn't have an S. I've beaten Sad Sniper EX with a 'B' which is good enough to win the VF-27 but I need at least an 'A' to win Brera.
I can get to Brera but what ends up happening is Alto gets killed so I don't get the bonus for keeping him alive or I don't kill Brera fast enough and he bails out. I tried to charge melee so I can boost close to Brera to use my SPA, but it never hits him clean or it just misses. Any tips on how to get a clean SPA on him?