i found this post by sebastian goetsch on the newtek forums:
‘the old ambient occlusion shader has finally found it’s way on the mac:
http://www.informatik.hu-berlin.de/~goetsch/AmbOcc/’
thanks again, sebastian, and thank you so much to ramprasad sampath for porting it to OSX!!
markus
ps. sorry for the double post - maybe the moderator can remove the first one please? thx.