Rendering a Ghost

Im working on a story, and it has a ghost in it.
I want to render a character in iray so they are nearly invisible, they are to be like a ghost.
But when i adjust the cut out opacity in daz their bodies turn into where you see right through their body, you see inside them, kind of like an xray.
This makes it hard to see the body and I do not want that, I want them to be a solid colour, and not see through, I am wanting more like a fading away effect. How can i get that effect?