T.O.
We had the same problem with my daughter until she was six. During the day she was potty trained at 3 but at night she still wore pull ups, finally I just bought several waterproof pads and put her in panties. It took about a week but she soon began to recognize the feeling at night. She is 8 and still has an occasional accident partly because she is a very sound sleeper. It will take time and patience, good luck.