ehhhh! the meshes are rendered correcly, my very last problem being is that the z-axis is still pointing up.
My apologizes, I have skipped the rotation of Z axis at load time, rather, I did a 90 degrees flip in the X and -180 degrees in Z.
It looks really strange in the viewport in 3ds max. But I don't really mind. But I am not accustomed to Z-axis pointing up.