Hi Robin!
It seems you want to have CoronaBitmap being both a common Texture map and an Environment map - I'd like to ask you to divide these into separate map types.
With a dedicated Environment Map you could ideally add arbitrary rotations (so non-Vray users finally can rotate in horizontal and vertical direction) and probably, gamma value (very useful for obtaining harder shadows when the dynamic range of the hdr map isn't sufficient), and different mapping types (cylindric, spherical etc).