Thanks to BB for linking to this thread from a new one I created, asking about the same topic earlier today.  I'll just follow up the question via this thread.

Ok, using the example from your original post, I set up an AO node on the material for the floor I'm using and tweaked it a bit to try and suit my scene.  This is what I got:

Now... how do I soften the contact shadow under her left foot?  It's looking a bit rough at the moment.  Also, should the shadow under the tip of her right heel be there?