Component not always applying the priority

The initial need was to add some additional property in the PDF export Job. With the old FOP export it was quite easy to retrieve the request parameter in the PDF template because we had access to the request object with all export parameter. With the new web export it's not possible as it's done asynchronously and the mapping from the request to the Job is done in the DefaultPDFExportJobRequestFactory that's why I need to override it.