Hi Ralf,
Creating Synonyms is not SPS6 specific problem and creating synonyms for all Currency tables remove the package prefix
Currency Conversion feature has been there in HANA for a long time while this package prefix concept came with SPS05 and I guess it has not yet been integrated with package naming convention and thus Currency Conversion can't deal with the package prefix on the front of the table names
If you read the HANA SHINE Guide based on SPS07 that deals with EPM Demo Content, it clearly states that:
"You must run the data generation tool at least to create synonyms."
": Re-creates synonyms for the following tables, to enable currency conversions" - all Currency tables are mentioned there
Please read the below guide
http://help.sap.com/hana_one/SAP_HANA_Interactive_Education_SHINE_en.pdf
So moving from SPS06 to SPS07 is not going to help you
And from what I have observed, at present only AWS has SPS07 while Cloudshare is generally updated late
Regards,
Vivek