No officer, department, board, agency, commission or instrumentality of state government shall employ any person to act as attorney, counsel, solicitor, legal assistant or other legal advisor to such officer, department, board, agency, commission or instrumentality except as otherwise set forth in this chapter. However, such special counsel may be employed by such officer, department, board, agency, commission or instrumentality with the approval of the Attorney General and the Governor upon such terms and conditions as the Attorney General and the Governor may prescribe. The special counsel so appointed shall have such powers, duties and responsibilities as designated by the Attorney General in addition to those powers prescribed in § 2504(3) of this title. Expenses of such employment shall be paid by the State Treasurer out of general funds not otherwise appropriated upon the approval of the Attorney General and the Governor.