There are several ways to do this and help the DD. One would be put a brick or block of wood (2x4) under her back heel at a 45 degree angle and have her take swings using a tee. Focus on her first move being turning the back hip. If she is getting a good turn that back foot should be up on its toe. Do not let her squish the bug.
Another would be have her stride off the bottom step of a set of stairs and simulate a swing. The back foot will end up on its toe just as described above. She will feel the weight of her body move forward as she rotates her hips.
My favorite method and one that a friend of mine (Steve Englishbey) uses is a mini trampoline. Place the front foot on the edge of the tramp and the back foot in the middle. Have the hitter stride down off the tramp. At foot plant the hitter tilts and turns hard to the ball QUICKLY. (Key Word) But still in control of the swing. As one of my favorite coaches used to say. (John Wooden) Be quick but dont hurry. You dont want the hitter to loose balance in this drill. Again like above your DD will feel the weight transfer and she will hit the ball much harder than you ever thought she would with a bat.
Give it a try and let me know how these work for you.
Ricky, does she transfer the weight during practice but not in the game, or not in practice either? I guess the question is does she understand she should but is having trouble executing, or does she not understand the concept?