Hi ecoull. In the almost 16 years that I have been dealing with many carbon parts, this is only the 3rd time that I have heard of a carbon post stuck in a carbon tube. Don't be embarrassed if you recognize number one.
The first encounter I had with this was a friend who had mounted a tail-light immediately below the binder on the seat tube. He had tightened the bolt in the plastic band enough that it kept the seatpost secure even with the binder loose. (I recently did the same on a new aluminum road bike of mine with a carbon post. Couldn't believe it!)
The second time was a bike that belonged to a very heavy sweater. I literally removed a ring of salt from the joint with a fingernail before i began with a dental pick. Sweat had worked its way between the two carbon parts. Salt is put on icy roads for more reason than to melt it!
Carbon-on-carbon is, by nature, slick and will not bond to itself except under long-term, high heat conditions that soften the resins that the CF is held in shape by. This is why carbon to carbon parts advise that we use a grip paste in place of grease. Trouble is... grip paste is not as water-proof as grease. More trouble is... a lot of greases (and other petro chems) can actually soften resins if not compatible. Do not use WD-40. Please?
If you think it may be 'salt-seize' (acidic), you need an alkaline to break it. Try Baking Soda mixed with water like you would use on a battery post in your truck. Pour it on repeatedly for 3 or 4 days. 16 soakings or more.
If the above is of no use, try
http://www.parktool.com/blog/repair-help/seized-seatposts-and-stems . If that doesn't help, a pic for us may!
Rob
Wheelies don't pop themselves. (from a QBP fortune cookie)