Neb. Rev. Stat. § 43-4612

An agreement or power of attorney under sections 43-4608 to 43-4612 must be filed within a reasonable time with any court that has entered an order on custodial responsibility or child support that is in effect concerning the child who is the subject of the agreement or power. The case number and heading of the pending case concerning custodial responsibility or child support must be provided to the court with the agreement or power.