Adding Custom OID in Certificate Template

Environment : Windows Server 2012 Root CA, 2008 R2 SubCA (One for ECC and One for RSA)

How can I add a Custom OID thru CSR, I can add a Custom OID and it value by Requesting new certificate using certtmpl.msc, works erfectky fine, I am trying to automate this process but not successful.

also, when I use certtmpl.msc and add custom oid, it recognizes the name of custom oid I passed, it means it is defined correctly. based on that Can I assume I have policies defined for that OID 2.16.840.1.101.3.6.9.1?

To me, my CSR looks correct to me becoz I have placed the OID at the same level as SAN(Subject Alternative name). I can create certificate successfully no error but my oid and value does not show up in certificate.

Any Guidance, documentation and suggestion will be a great help.

Please let me know if more information is required.

Thanks !