perforated material

[lalablabla]

Hi,
I'm a fresh new keyshot2 user and I was wondering how I can make a perforated material (I need to make a kind of "opening wicker" ). I've seen that there is some perforatedd material in the keyshot library as leather for exemple, but I dont really understant how it works... Is there anybody who know where I can find the transparency map (because I only see specular, bump and texture map) ?
Thank a lot for your answers