Bending loss can be indirectly extracted by using the “Relative Power vs Distance” plot. This is enabled in the “Additional Output Options” selection under the “Simulation” Menu.
Run a simulation with a given radius and you can extract the power transmitted relative to input. You can convert this to a loss and from there an alpha. You would then run a parameter sweep where you change the radius and would have results for multiple radii allowing you to generate the bending loss versus bending radius.