Hmmmm diferent aproach similar solution 
Of course the SalesOrderCRMAttachmentFolderByIDQueryResponse_In will end up using the CL_CRM_DOCUMENTS but I prefer to take as base the SalesOrderCRMAttachmentFolderByIDQueryResponse_In in order to use the same interface for the attachments (WSDL) like the standard and don't miss any functionality that maybe I will need in the future (like the document properties)
Good stuff
Luis
Message was edited by: Luís Pérez Grau