uch action or proceeding shall be deemed to be an action or proceeding brought against the United States under the provisions of this title and all references thereto, and the United States shall be substituted as the party defendant.   This certification of the Attorney General shall conclusively establish scope of office or employment for purposes of removal. 00 U.S.C. § 0000(d)(0) (emphasis added).   0  Section 0000(d)(0) provides in full that: In the event that the Attorney General has refused to certify scope of 