creating material surface pattern files?

[vanderloo5]

I would like to create a new wood shake surface pattern because the existing one is scaled waaaay too small. I've read I need to create a new pattern by importing the existing one, then give it a new name, and change the scale. Can someone confirm this is the best way. I would also like to know where the material files are located so I can import an existing one. Can't seem to locate it in the help files.
Thanks

[vanderloo5]

Found the fill .pat files in C:/Program Files/Revit Architecture 2009/Data/Revit (pat)