What Chombi and Rootboy said, Campagnolo's replacements, and Kool Stop's pads, both will do the job quite well. The Kool Stop are available in the black or a softer, wet condition, salmon colored pad. If the squealing continues you might have to chamfer the pads and remove the glaze that they have when new. Some fine grit sand paper, a Dremel tool works well with the drum sanding bits, and just rough the flat up somewhat. You may need to angle the faces so that the pad doesn't hit the rim parallel, but the trailing edge comes in contact first. The Campagnolo replacements look very much the same, but the blocks now have an "X" cut, rather than the separate squares. I just watch eBay for the originals, or use Kool Stop's Salmons (both are in use right now.)

Some folks prefer to bend the brake arms, I wouldn't advise using that method, those are Super Record calipers and are really getting expensive to dig up. NOS ones can run you upwards of $350.00 or more, without the pad carriers and levers.