Any labor union or labor organization doing business in this Commonwealth, all of whose officers and trustees are nonresidents of this Commonwealth, shall by written power of attorney, filed with the Department of Labor and Industry and the State Corporation Commission, appoint the clerk of the State Corporation Commission its attorney or agent upon whom all legal process against the union or organization may be served, and who shall be authorized to enter an appearance on its behalf. The manner of service of process on the clerk of the State Corporation Commission, the mailing thereof to the labor union or organization, the fees therefor, the effect of judgments, decrees and orders, and the procedure in cases where no power of attorney is filed as required, shall be the same as provided for in cases of foreign corporations.