The latest news is:
"Mechanic Nick Vandercauter told Cyclingnews that while Scandium is standard issue for all, full carbon jobbies are used during the Giro d'Italia, certain World Cups and the Tour de France. "Some riders, like Serge Baguet who suffers from back problems, have found the carbon bike to be too stiff, so Serge went back to the aluminium model after last year's Tour," added Vandercauter."
http://www.cyclingnews.com/teamtech04.php?id=tech/2004/probikes/lottodomo_merckx
"Mechanic Nick Vandercauter told Cyclingnews that while Scandium is standard issue for all, full carbon jobbies are used during the Giro d'Italia, certain World Cups and the Tour de France. "Some riders, like Serge Baguet who suffers from back problems, have found the carbon bike to be too stiff, so Serge went back to the aluminium model after last year's Tour," added Vandercauter."
http://www.cyclingnews.com/teamtech04.php?id=tech/2004/probikes/lottodomo_merckx