You have to apply a material like
fx_bump
mtl_bump
fx_specBump
mtl_specBump

Requires normal map on second skin.


You can read about it in the manual under "shaders" and "shaders library":
http://www.conitec.net/beta/amaterial2.htm

Quote:
*NM: Supports a normal map on the second or third skin, dependent on whether a lightmap is used.