To incorporate, where civil law permits and when authorized by the district assembly. After incorporation, as above provided, the District Advisory Board shall have power, on its own resolution, to purchase, own, sell, exchange, mortgage, deed in trust, hypothecate, lease, and convey any property, real and personal, as may be necessary or convenient for the purpose of the corporation. The district superintendent and the secretary of the District Advisory Board, or other persons authorized by the District Advisory Board, incorporated or not incorporated, shall execute and sign all conveyances on real estate, mortgages, releases of mortgages, contracts, and other legal documents of the District Advisory Board. (206)