There's also a book "LightWorks in Archicad" that deals extensively with materials [surfaces]. See below for ordering.
As for your specific issue, a hidden feature of LightWorks is a non-implemented material archive. The attached dialog composite shows how to access a LightWorks 'shader' in this archive offering a variety of wood types. A 'shader' is merely a programmed pattern generator.
Dwight Atkinson