no encoder for type "{http://www.w3.org/2001/XMLSchema}base64Binary" and Java type "java.lang.Byte[]

We have an application with OAF in JDeveloper 9 which use web services to acces  WCC (checkin, checkout and ...).

We are updating our ebusiness suite to R12 so we have to migrate this application in JDeveloper 10.

We have re-generate stub files from wsdl and now when we launch the application, we have this error :

Oracle Containers for J2EE 10g (10.1.3.3.0) initialized13/11/28 10:48:13 no encoder for type "{http://www.w3.org/2001/XMLSchema}base64Binary" and Java type "java.lang.Byte[]"13/11/28 10:48:13 at oracle.j2ee.ws.common.processor.generator.writer.LiteralSimpleSerializerWriter.<init>(LiteralSimpleSerializerWriter.java:49)13/11/28 10:48:13 at oracle.j2ee.ws.common.processor.generator.writer.SerializerWriterFactoryImpl.createWriter(SerializerWriterFactoryImpl.java:122)13/11/28 10:48:13 at oracle.j2ee.ws.common.processor.generator.LiteralEncoding.writeStaticSerializer(LiteralEncoding.java:58)....Any idea ?