Information on curved surface support starts on page 192 of the current V2.0 manual. However, we do not have support for a conical surface in the curved surface support.
One thing you can try is using a cone 3D object (there is one included with the stock content, object 58) and aligning the 3D object with your surface. The one draw back here is that you will have to do this for each layer, rather than once on a global level as with the curved surface support.
