Can this be done? Or does the DSP only work with SQL data sources?

In olap4j.properties I have these lines:

Buses.name=Buses
Buses.className=org.pentaho.platform.plugin.services.connections.PentahoSystemDriver
Buses.connectString=jdbc:mondrian4:Host=localhost;dbname=austin;DataServicesProvider=com.pentaho.analysis.mongo.MongoDataServicesProvider;Catalog=solution:/public/Schemas/Buses.xml;Locale=en_US;DynamicSchemaProcessor=mondrian.i18n.LocalizingDynamicSchemaProcessor;

I can run queries in Analyzer, and there are no errors in the log so I think it's loading the DSP OK, but it isn't doing any of the %{} substitutions.

(If I use an invalid DynamicSchemaProcessor name, eg DynamicSchemaProcessor=foo.bar , I see errors in the log which is why I think it is loading it OK)