Bobv,
I regularly layer Pianoteq with a sampled piano just to add the body resonance that Pianoteq can sometimes lack. You could probably use AK for the sampled piano although it can be a bit thin it sits in a mix nicely.
I use the Pianoteq Bluther (modeled) with a Galaxy D (sampled) and it really has a nice responsive feel plus sounds great for any solo piano stuff. I use just enough sampled to give that extra body resonance I can't seem to get from just the Bluther. I guess try mixing to taste!...