wow, saw the top part first as the internet downloaded the image, was bored at that point, then I saw the sand and water, really beautiful work done there.
Vue is an amazing piece of software (and one of my favorites), but it is still fairly obvious which clouds are from photos, and which are from the render. It's the edges that really give them away - I think you need to do a lot more painting / photo work to the cloud edges to make this scene look believable.