I am positioning the vray sun in-camera so that it appears just behind a particular bit of geometry. It is not connected to any kind of daylight system. When I render, the position of the sun ‘orb’ is very different to the viewport position.
How close is your sun node to the rest of your objects in the scene, Remember the Sun Position is supposed to be a few million miles away so you may need to move your sun light object back in distance a bit to get a more accurate viewport representation of where your sun is in the sky.