what are your solutions to better anchor the cable in a campy record front derailleur?

i recently bought a very pretty one, a three-hole version on ebay. but the groove in the arm for the cable to rest is a little too deep to allow the cable to anchor properly against the bolt/washer. if i use an additional washer so the cable no longer sits in the groove, i think it might work, even though it doesn't 'look' perfect. but i'd also like to know how you've solved any cable anchor problems with your vintage campy fd. many thanks.