Same issue I had. Thomson solved it. 
Remove the forward bolt, remove the cam from the opposite side, grease the cam, re-install.alee said:I have the Shaft seatpost on my Dos Niner with a WTB Speed V Saddle. No noise for the first 300 miles or so, but now it has started creaking. I know it is the seatpost clamp because when I get out of the saddle it goes away, and if I take the saddle off and grease everything the creak goes away for a ride or two. I have tried 2 different greases, and tightening everything up, but the creak comes back.
Anybody have any luck with this (or a good Thomson seatpost for sale?)?