In a medium bowl, combine vinegar, sugar, ketchup, ginger paste and soya sauce. In a large skillet, heat oil over medium high heat. Place chicken in skillet and cook, turning occasionally to brown on all sides, 10 min. Reduce heat to medium, and pour vinegar mixture into skillet, stirring to coat chicken. Cover and gently simmer, turning chicken once, 7 min. Add broccoli and continue to cook until chicken is cooked through, about 5 min.