Step 1 was in Message 6 of this thread. Add that gather node to the object you want the ambient light to show up on. Then add an object with a high ambient channel set to 1 and turn on Ray Tracing in your render settings. You might have to fiddle with the MaxDist (I set my MaxDist to 12 instead of 4 like the screen cap in message 6) settings to get the ground to reflect that ambient light but I got this image with no lights a ground prop with gather node, a Hi Res Spere with Gather node and a cylinder with a hi ambient texture on it. The only light sorce is the ambience channel of the Cylinder.