In fact, I understand now the usefulness of the method SetMetaDataFile and its impact on all SAS objects. Once the configuration files have been defined, I no longer need CreateObjectByLogicalName or CreateObjectByServer methods. Creating servers (SAS.Workspace, for example) is made by simple declaration.
obObjectFactory = New SASObjectManager.ObjectFactory
obObjectFactory.SetMetadataFile (ServerInfoFile, UserInfoFile, True)
obSAS = New SAS.Workspace
Thank's anyway