I feel your pain. I bet the page you're talking about is:
Lots of other good reading on their web-site, too.
I've got Ultegra also, but on my bike, the caps are only part of the rattling. The shift make a fair amount of racket, too. Throw in the roadbuzz from the carbon fork, and the racket from the rear brake cable pinging against the top-tube, it adds up to quite a racket. I fixed the pinging with one of those felt pads that are made to go on table legs, etc., to keep them from scratching the floor.
Anyhow, it really makes me appreciate the peace and quiet when I go for a ride on my old, skinny tube, 7-speed down-tube shifter, chrome-moly fork Bianchi.