The CA certificates and private key can be backed by calling NPKIExportCAKey function.
Call NPKIFindOrganizationalCA to get the DN of the CA. The CA name is the leaf name of the DN.
Call NPKIExportCAKey to export the CA’s private key and certificates into a personal information exchange (PFX) file. Store the PFX file in a secure place.
For a sample implementation of this task, see BackupCA.