Solution : https://service.sap.com/sap/support/notes/1474866 (SAP Service marketplace login required)
Summary : 
      
Key words : 
unauthenticated/unauthorized exceptions calling webservice methods, sap landscape virtualization management service configuration, sap landscape virtualization management, symptom unauthorized/unauthenticated errors, error calling webservice method, setup-> lvm -> engine configuration, <sid>adm user/password, <sid>adm credentials, check sap note 927637, dectection errors reason
Related Notes : 
       
| 1439348 | Extended security settings for sapstartsrv | 
| 927637 | Web service authentication in sapstartsrv as of Release 7.00 |