Facebook API PHP SDK geo_locations cities not working using radius and distance_unit

Question

I've problems using the geo_location when publishing automated posts on my facebook page.

It is possibile to use range in the geo_location?

I have this array :

            Array
            (
                [geo_locations] => Array
                    (
                        [countries] => Array
                            (
                                [0] => IT
                            )

                        [regions] => Array
                            (
                                [0] => Array
                                    (
                                        [key] => 1852
                                    )

                            )

                        [cities] => Array
                            (
                                [0] => Array
                                    (
                                        [key] => 1184654
                                        [radius] => 50
                                        [distance_unit] => kilometer
                                    )

                            )

                    )

            )

but i get this error from Graph:

            Graph returned an error: (#100) Invalid keys "radius, distance_unit" were found in param "targeting[geo_locations][cities][0]".

If i delete the Key "radius" and "distance_unit" manteining just the key "Key" everythings is ok and the post is published.