As rmac wrote, the Campy Ultra-Shift will work with just about any front derailleur, noting Campy's Ergo levers aren't specific to double or triple front derailleurs either. Campy's left-hand Ergo's close-ratio "Micrometrical’ indexing is truly a wonderful thing for tandems.

FWIW, the Ultra-Shift simply brought a decrease in lever travel to the left-hand Ergo shifter that controls the front derailleur movement such that it takes about 1/5 as much lever movement to move the front derailleur X distance as it did on the previous generation Ergo lever, i.e., similar shifts will take less hand movement on the Ultra-Shift.