Yes brother, you can use the Nikah Nama for Marriage certificate. I am from South india and my Nikah nama is in Tamil language. When i came here to Qatar and had to apply for Family RP in 2009. I gave the copy of this Nikah nama to ASIA Translation for translation in English and they will attest the document(just check now, whether anything new).
I sent the Original Nikah nama(actually i have 2 set of original copies) to Mumbai for attestation from MOE. I did this thru agency in qatar.
I attested the following documents
My Degree certificate, My Marriage certificate and my child birth certificate.

Hope this info is helpful for all, incase new rule is not amended.