you have to bake a heightmaptexture. bake it in the illumination channel with a black/white gradient and change the gradient to 3D linear and set the y-values to -100 (start) and 100 (end), i think it should be baked in 16bit. then save it in photoshop as photoshopraw non-interleaved and it should work. (worked here with R10.5 and Photoshop elements)