How to install that shade ...

- > https://highend3d.com/xsi/downloads/s...lSky-4375.html


and when i place the maya file in my Maya 8.5 it get's me an error
/ Warning: file: C:/Documents and Settings/COlD/Desktop/HDRI/mad_physicalSky_v1.1/mad_physicalSky_example.ma line 1157: Unrecognized node type 'mad_physicalSky'; preserving node information during this session. //
// File read in 0 second

And see on the pic below i must choose a enviorment shader "Mad_..." I don't have this shader to choose ...