Liberator on Atari Classics (Xbox)

[elviticus]

I've been really getting into Liberator on Atari Classics for the Xbox. It's a really cool game, but one thing bugs me.... How do you (can you?) activate the shield? I see there's a shield button on the arcade cabinet pics, but can't figure out how to do anything but fire on the Xbox.... Anyone?

[Austin]

I am terrible at that game. Sorry, just thought I'd mention that.