I've done this upgrade on a Shimano equip. bike before, I assume that it will be the same for Campy. Not only you will need to replace the BB for a longer one but also, you need to replace the front dérailleur for one design for triple and also the rear dérailleur with one with longer cage. This is an expen$$ive upgrade. Compact crankset could be a cheaper solution, a 50-36 or 50-34,.