Extending the list of named colors in Sketchup:

Developers Ruby API
3

Now if you absolutely wished to use materials with names as they were spelled in the SVG file, then you can call the get_safe_color() method from another method:

  def make_svg_material(name, matls = Sketchup.active_model.materials)
    matl = matls.add(name)
    matl.color= get_safe_color(name)
    # set any other material properties here
    return matl
  end