It looks like that both .aga and .ama files actually come from ArcGIS software, to be more precise from ArcGlobe and ArcMap respectively. We have not found any kind of sources that would describe aga to ama conversion or its potential use, but perhaps something like that or similar export is doable.
If you are determined such conversion should be indeed possible and struggle with it, it might be best to reach out to ESRI / ArcGIS support or to the online community or social networks.