Hi Alexander,
Currently the schema mapping don't change the authoring system on XML's files but points to the desired SCHEMA_2, at least with maintaining the schema mapping.
One thing I didn't tested is about .hdbschema if it works on schema mapping as this object should be used for creationg of it, not consuming.
Observation: If your artifacts are script based calculation or procedure and you put the schema hardcoded on text inside your scripts it's not subject to change with schema mapping functionality. SM only works for properties like default schema, graph objects...
Regards, Fernando Da Rós