When I opened my PNB online remittance account last year they accepted my Passport/Utility Bill being authenticated by a post/sub-post master. Go along to your local post office with copies and your original documents and they should stamp and authorise the documents as original.
I also typed out a short letter saying that the documents were validated as true and that was also stamped. Only post off your copies to PNB. I was not charged for this and the account was opened.