Normalize Cycles' UV render pass output to value range [0,1]

If I want to use this render pass outside of Blender (e.g. to change texture of an object in an image, together with the object index render pass), having the value range already normalized can really facilitate the process. Currently it doesn't seem to be the case - for non-trivial renders, even with trivial object of interest (a plane), I get e.g. UV range of [-13,24]. I'm not sure it's a bug of my code (I use OpenEXR multilayer and able to reconstruct the combined image from the .exr file with saved passes in python).