Shimano to campag. swop/ Compatability

Hi All.
I'm a relitive new comer to road bikes having riden mountian bikes for years. When I purchased my bike I wasn't 100% sure I was going to stick with it so didn't spend as much as I would have on the bike. I ended up with a Sora equip'ed bike which is not that bad apart from the front mech, which is horid. The casting in the (braze on) clamp area is not very good and no matter how much time I take setting the alignment it always moves to "where it wants to be" when the clamp bolt is tightened fully.

Anyway I'd like to change to Campag stuff eventually and was wondering if it is possible to do some of the change gradually.
My question is can I change the Mechs on thier own first? will they work with Shimano chains, sprockets and cassettes?
I know that Campag and Shimano hubs/freewheels and chain rings are not interchangable, but but as far as I see it the mechs must be. afterall they just shunt the chain a given distance set by the lever.

cheers Jester