'''96 Litespeed Catalyst, '05 Litespeed Firenze, '06 Litespeed Tuscany, '12 Surly Pacer, All are 3x8,9 or 10. It is hilly around here!
The problem is the geometry may not work. Shimano STI levers front shifters are indexed and pull a specific amount of cable per "click". Shimano front derailleurs are designed to index properly with their own shifters.
Campy front derailleurs are not designed to be compatible with Shimano shifters and the only way to find out is to try it. You may luck out but that's what it would be,.... luck.
Ironically, going the other way usually works fine. Campy Ergo front shifters are ratcheted rather than indexed and will usually shift fine with nearly any front derailleur.