Ok well luckily for you i just installed the amuse bar yesterday night so i can show you where it mounts...but since im retarded i didnt take many pictures so its not all that great.
In the picture below you can see the circle i threw on there. It shows a "flange" that is welded to the car itself...thats the bottom side. There is another piece almost the same size that mounts to the car via 4 bolts that you remove to pull out the bar.
You can see what im talking about in this photo when i was putting the amuse bar back in. The bar sits on that bottom bit, then you put the top pieces back on and bolt them back into the car, then you run the 2 bolts per side through the bar itself and then start putting the million pieces of interior panels you had to remove... back on the car.
Hope this helps!