I've searched the internet and so have read a few rebuilds and watched some videos, but would like to be absolutely sure I know what is going on with my Veloce shifter. The right 10 speed will shift fine when there is no cable connected, but once you hook it up to the derailleur, it starts skipping gears when you shift up using the trigger. Sometimes it will shift all the way to the bottom of the cassette, and then when you try to shift down using the paddle, it won't catch and will just shift down and up and down and up, and you have to do some fiddling to get it to catch again.
I watched this video http://www.youtube.com/watch?v=8Y5Sn_Jnkus and the shifters have the same internals. Which parts would be replaced to stop this happening, assuming the parts are even available?
I pulled mine apart and didn't see anything obvious, so I don't know if it's just one of the springs not having enough tension to overcome the derailleur spring.