>>After check it again, Zsurf support for spherical also.<<

and you can use bitmap as "basesurf"
import bowl in rhino3d and see command "testshowzbuffer" from topview
after import this picture as "basesurf->bitmap" in zsurf, option "custom resolution", adjust "z-high" and combine this with other "ornamentmap".

and how it looks with Rhino3d -> UDT-Tools???