schematron support in Oracle SOA 11g PS3

 I am looking at using schematron to validate an xml message with a Oracle 11g SCA project. I have sucessfully used the schematron validator with a mediator component. However I would like do schematron validation within a BPEL process so that I can create a generic schematron validate that uses different rules depending upon the input message.

My first approach was to take the method outlined in this blog http://blogs.oracle.com/rammenon/2008/10/using_schematron_within_bpel.html . This now seems to be out of date and as there is no source for the SchematronValidator class, it is tricky to reengineer it for 11g. The next approach was to take the example from the Packt book "Oracle SOA Suite Developers Guide" . In this, it suggests using the validation.wsdl from the bpm-services.jar and invoke it from BPEL. This works OK but always returns an empty ValidationErrors element even when the data is obviously incorrect.