Only the rebound area is adjustable, compression is not varied by the adjuster- see the below graph from the Koni website:
The yellow area is for the Sports externally adjustable range- compression and rebound are labelled to the right of the graph. Go here for the full page:http://www.koni.com/_cars/_general_info/technology/damping_forces.html
Below is a cross sectional diagram from the same site of a top adjustable Koni Sport damper- note the gas reservoir (in blue). Follow the link below the image for the full page, and then click on figure B.
http://www.koni.com/_cars/_general_info/technology/construction/shockabs.html 
