In bryce 5, there is a file in called user.mat that is just like 1k or something (it's really small) and it's in the main presets folder. Duplicate that file and call it whatever you want .mat. Then in bryce there is a new category! You need to unzip all of the materials outside of bryce and then you have to go to the presets menu, select the new category, and import the materials into the right places. Hint: You can also duplicate the user.mat file and turn it into user.obp, user.brt, user.bsk, and it will allow you to do the same things for materials, objects, and skies.