Need Part for Older Campy Front Derailleur

I have a lovely all-Campagnolo tandem -- about 15 years old.

The front derailleur self destructed on the clamp's hinge and I'm looking
for either a replacement derailleur or one that I can cannibalize to fix the
clamp.
(New Campy front derailleurs unfortunately are not capable of handling the
wide span of gearing on my triple chainrings.)

The old clamp is 28.5 mm.

If you reference the attached jpeg, you'll see the configuration of the pins
and adjusting screws, which is much different from today's product.

If you can help, please advise.

Thanks.