SCRIPT_export with origin in dwg using cplane origin

Hi,

I’m trying to code a command that would exportwith origin a slection of objects.
The origin of the export has to be the origin of a given cplane (that would be called export) multiplied by -1.

For instance : i would like to export with origin this object using this cplane wich has this coordinates at its origin (5;5;5). The command would export with origin and the point that has these coordinates (-5;-5;-5)

Could you provide any ressources that can help me build this command,
Thanks a lot !