While Izotope seems unable to provide a version of RX that run in SO6 through ARA2 (and that's a shame because they did it for Logic!), Acon Digital provides its Acoustica Editor that is fully compliant with ARA2.
But it seems that S06 coders have to authorize the use of Acoustica just like they did for Melodyne and VocAlign...
So, as James Brown says : Please, please, please, pleaaaaase!