Work in progress...
At the moment only Virtuoso is supported. Make sure these priviledges are set:
GRANT EXECUTE ON DB.DBA.SPARQL_INSERT_DICT_CONTENT TO "SPARQL";
GRANT EXECUTE ON DB.DBA.SPARQL_DELETE_DICT_CONTENT TO "SPARQL";
Make also sure that the triple store and its SPARQL endpoint are not accessible from the outside. It is recommended to use a separate Virtuoso instance just for this.