I've had one go; throttle side, though.
When I got a replacement I was pretty cautious about not over-tightening the screws.
IIRC, Ducati only sell the clamp and the clip-on bar itself together as a unit.
And they're quite dear.
checks records I paid £66.84 + VAT. In 2002.
However, they often come up on ebay, much cheaper.
Or someone here may have a spare they're prepared to part with.
[Edited on 3-4-2005 by moto748]