EDIT damm, wrong forum.

Took a cage from a broken Shimano XC and made a mounting plate as neither the pivot bolts nor the spring hole were the same; said plate fixed to the long cage with 4 stainless screws.
On top, the long cage plate, below the original Campag one:




The Victory has a stop adjustment widget that
a) breaks; and
b) is a bad idea anyway - you have to remove the mech from the frame to change stop positions.
It's inside the knuckle and has teeth to set the position.
It breaks because it's made of some sort of alloy only a bit stronger than cheese.
Here's the broken on in situ:



So I made a different insert that has an external screw for adjustment; turned a ring and sawed/filed a bit to silver-solder to the ring, drilled and tapped for a screw
Here are the (broken) original and the one I made - the section that goes in where the teeth are has no teeth, instead it fills the space as it does not have to move:





The adjustment screw:



And on the mech: