There's a lot of variables that go into swapping a fork. If it's different length or has different rake it will affect geometry and handling (might be relevant, might not be). Headset and frame compatability is another factor to consider. Carbon frames often have integrated or semi integrated headsets meaning that the frame might be the bearing seat. This means that getting the correct headset... combination say, on a surly steel fork for example can prove challenging.
Don't clamp stuff around carbon tubes if that's not specifically allowed by the manufacturer. if the part you're clamping isn't reinforced for that sort of thing you risk damage.
So i short, if you don't know exactly what you're doing and how the headset/geometry thing is going to work out, don't do it.