NEW YORK - A key accuser at the R. Kelly sex-trafficking trial returned to the witness stand on Thursday, saying he often videotaped their sexual encounters and demanded she dress like a Girl Scout during a relationship that began when she was a minor.Jerhonda Pace resumed her testimony in Brooklyn federal court a day after telling jurors she was a 16-year-old virgin and a member of Kelly’s fan club when he invited her to his mansion in 2010.