If you look at the top of the caliper arm where the adjuster goes it is a D shape with no thread? Modern fittings are far as I am aware do not fit these brakes .. you could try http://www.campyoldy.co.uk/ as he used to stock a lot of old spares. Also have a look at this page 38 which shows spare parts numbers http://www.campyonly.com/history/catalogs/catalog_17a.pdf
If you look at the top of the caliper arm where the adjuster goes it is a D shape with no thread? Modern fittings are far as I am aware do not fit these brakes .. you could try http://www.campyoldy.co.uk/ as he used to stock a lot of old spares. Also have a look at this page 38 which shows spare parts numbers http://www.campyonly.com/history/catalogs/catalog_17a.pdf