A St. Croix County judge has sentenced a Somerset man to 30 years in prison for sexually assaulting a child.  Prosecutors told the court Richard Maness used the victim to make child pornography.  Investigators say he assaulted the girl for several years, starting when she was nine years old.  When deputies served a search warrant at his home, they found naked pictures of the girl and homemade videos of naked children.  Investigators say the photos they seized also showed Maness’ ex-wife sexually assaulting a two-year-old  boy.  Jennifer Bowers is scheduled to be sentenced at the end of this month.