Yep, you\'re stuck.
The reason is that the FA-MAS wasn\'t meant to be "playable" in the demo, so it\'s not set-up properly.
No biggie, you can still off Olga very quickly with it. Also hold down the
L1 button while running and shooting, I heard it "locks-on" to targets.
Also with the C-4, even though it blows it won\'t do total enviornmental damage, because that hasn\'t been incorporated in the demo either (the C-4 that is). You can still blow some things.