Unfortunately, I think that this would require development to support. Because of the unique way that AtoM and Archivematica have developed separately (and the business model we've had to use thus far to support them - described further in the second half of
this wiki page), there are some integrations that we'd very much like to see between the two applications that aren't currently supported. Artefactual is trying to evolve its business model and development approach while still ensuring we can continue to support our projects, so hopefully in the long term these kinds of gaps will become fewer. In the meantime however, we would need community support - either in the form of code contributions or development sponsorship - to be able to enhance the AtoM-Archivematica integration with further configuration options, such as passing the original filename instead of the sanitized one.