If you're staying with 8s you'll probably be able to get by with a new (2001+) derailleur. I was Campy's east coast service tech at the time 10s came out and the RD platform changed (new ones don't have a "B" screw on top). They brought out a new version of the 9s cam for ergolevers, but opted not to mane a new 8s version. Their reasoning was that the difference in geometry was small and while it would affect 9s shifting, 8s was coarse enough to get by with the older cams.
I serviced a number of warranties in that era, sending new geometry 9s derailleurs to replace dead 8s ones, and nobody needed to recam the levers. If you can find an old derailleur that would be best, but if not a 9s or 10s derailleur combined with a 9s chain will work fine.
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