I just discovered that SolidWorks hatch patterns (defined in sldwks.ptn file) are defined exactly the same way as in Autocad (acad.pat). So if you need a special hatch pattern, just download one for Autocad (there are plenty of free ones around) or use one of the many available tools to generate it, then cut/paste in the sldwks.ptn file. Great, isn't it ?
-- Philippe Guglielmetti -