v-brakes generally need a lot more cable pull than a canti as they are linear, so depending on the levers you have, when you pull it, the cable may not move far enough to get good braking.

E-bay?

I have to confess, in the last week I've bought 2 frames and a complete bike from e-bay. It's a bad habit but man they were so cheap !!! I couldn't help it.

Now I need a post style Campy front derailleur, better go searching...