Do you know or possibly have a concrete example of how Daminion stores its tags? If they are stored as standard XMP, they should be imported and displayed in Aspect fine. If it instead just stores them in some kind of proprietary catalog, this would require a custom importer, similar to the Aperture importer extension. I could have a look at this if you can provide a small example library where you have one or two smallish images with some tags assigned.