There is no way around this requirement for the Statement to come from the DGCA, as it is a specific requirement for FAA importation, and the CAA requirement in order to issue the Export C of A for an aircraft heading for FAA Registration. It is a Statement that at initial build, the product complied with and was certified under the Civil Regulations of the time - specifically, not a military product.
As RVDT notes this issue runs back to a very long legal battle with the FAA over imported Sud-Aviation Allouette 2 & 3 helicopters that had their Standard Airworthiness Certificates revoked (
Alouette Helicopters Declared Illegal Immigrants By The Faa).
It is probably best to engage with your local Airbus tech rep to assist you in getting this Statement. Have all your paperwork ready, including initial C of A and submit it, or better still arrange a meeting and take it all with you - I know of no alternate means of compliance.
Bit of background reading which may probably explain the intransigence.
http://www.ca4.uscourts.gov/Opinions...d/102355.P.pdf
http://www.airweb.faa.gov/Regulatory.../N8300_124.pdf