@Override
 public List<SignatureVo> getAllSignatures(UserVo userVo, DocumentVo documentVo) {
   Account actor = accountService.findByLsUuid(userVo.getLsUuid());
   try {
     DocumentEntry document = documentEntryService.findById(actor, documentVo.getIdentifier());
     return signatureTransformer.disassembleList(
         new ArrayList<Signature>(document.getDocument().getSignatures()));
   } catch (BusinessException e) {
     logger.error("Can't find document : " + documentVo.getIdentifier() + ": " + e.getMessage());
   }
   return null;
 }