Fitting a saddle with non-round rails to a Stevens Arcalis What options are there to change the saddle mount on an aero seatpost of an Stevens Arcalis 2017 to mount a saddle with non-round carbon rails?

Below you can see the saddle mount that is designed to accept round saddle rails only. Usually 6mm x 6mm or 7mm by 7mm. 

Are there any options&nbsp;&ndash; specific to this bike or general purpose&nbsp;&ndash; to allow that?



Update:

Stevens Vertriebs GmbH (info@stevensbikes.de) informed me via email


  ... we are sorry, we don´t have Arcalis saddle clamps for Carbon-Rail
  available


So stevens does not provide any replacement part for my purpose.
As the "Stevens Vertriebs GmbH" and other sources on the internet mentioned there is probably no 3rd party solution as of now to mount another saddle which has no round bars.

UPDATE:

I sanded down the carbon rails of the saddle to make them fit.
When doing this wear a breath protection and protect you and your environment from the carbon particles.