I just found face_off's tutorial on AO and it seems pretty straight forward, although time consuming, but I do have a question about it.  In the tut he says to use the set up AO wacro to get the node initialy.  He goes on to say that if there is anything plugged into Alt_Specular or Alt_Diffuse, the nodes need to be set up by hand using a color math node in those channels with whatever else plugged into that.  My question is does this replace the AO node that the wacro set up or is it in addition to it?  If it replaces it, how do you set the samples, ray bias, etc...?  And, if there is only something plugged into the alt_specular, is the color math node needed in alt_diffuse or only in alt_specular?