I don't think you have an option to chose the vDS version.
If you deploy VxRail 4.0.X you get vDS v6.0.
If you deploy VxRail 4.5.X you get vDS v6.5.
Thank you for your answer. I know wich vDS is shipped with the VxRail versions. I was wondering if a customer have the choice to select the vDS version during the initial VxRail setup.