Thanks, Jasmin!
I've referenced to repository as you proposed but still when it comes to RepositoryService to read the DDX file I have the following exception in the Jboss log:
SEVERE: JobManager:getServiceClientFactory(userContext):invocation context is null, using null context to create job
2007-11-15 09:07:00,803 INFO [STDOUT] 15/11/2007 09:07:00 com.adobe.idp.jobmanager.ejb.JobManagerBean doOnMessage
SEVERE: JobManagerBean:onMessage():Exception:ALC-DSC-213-000: com.adobe.idp.dsc.DSCException: No Credential or Context set
2007-11-15 09:07:00,803 INFO [STDOUT] ALC-DSC-213-000: com.adobe.idp.dsc.DSCException: No Credential or Context set
Rbuz.