For the purposes of this Article:
Service which under the Social Security Act may be included in an agreement only upon certification by the Governor in accordance with section 218(d)(3) of that act shall be included in the term "employment" if and when the Governor issues, with respect to such service, a certificate to the Secretary of Health, Education and Welfare pursuant to G.S. 135-29.
N.C. Gen. Stat. § 135-20