from what i can tell, in a Holmegaard bow the entire length of each limb bends, where as the Mollegabet style bow has the inner half of each limb bending with he outer half working as a lever. Im not too sure why these bows are so closely related though.
Edit: If it worked right, the top pic is a Mollegabet Bow, the Bottom is the best i could find for a bow modeled after the Holmegaard bow.