Wis. Stat. § 767.14

In any action affecting the family, each party shall, either within 20 days after making service on the opposite party of any petition or pleading or before filing such petition or pleading in court, serve a copy of the same upon the circuit court commissioner supervising the office of family court commissioner of the county in which the action is begun, whether such action is contested or not. No judgment in any such action shall be granted unless this section is complied with except when otherwise ordered by the court. A circuit court commissioner assisting in matters affecting the family may appear in an action under this chapter when appropriate; and shall appear when requested by the court.