Hi Ralf,
In the above URL, did you replace server name and instance name?
Check SAP_HANA_DEMO schema and check Synonyms there
Alternatively, you can create Synonyms in HANA Studio using SQL
The belwo statement creates a Synonym for TCURC table
CREATE SYNONYM "SAP_HANA_DEMO"."TCURC" for "SAP_HANA_DEMO"."sap.hana.democontent.epm.data::EPM.Conversions.TCURC";
Similarly create synonyms for other Currency Conversion tables also
Regards,
Vivek