Pulling down is one of the areas we're emphasizing this year with our starter and the new girl I'm training. Have your DD get to the nine o'clock position, ball up, and put your hand on her triceps, where it meets the elbow. Have her pull down and push on your hand with the back of her arm while you provide resistance, this is abduction. If she focuses on pulling down hard like that when she drills and/or pitches the IR will happen naturally, there will be no thinking about or forcing the rotation to happen. The forearm/wrist and ball will just spin or rotate into the pitch. It's takes a while to control it but that is how you snap throw like a whip versus muscling a throw, which is what my number one pitcher does. She's good at muscling it but she can be so much better. Right now she nips 55 with muscle, my expectation is hitting 60 with snap throws. Our goals this year are to pull down versus muscle, harder drive off the rubber (thanks Java), better breaking and rigidity on the plant for maximum transfer of energy into the ball. We've come a long ways, this is the final adjustment for her senior year.
When converting a girl (and her parents) from pushing a ball to using IR, use the above technique but also have her put the ball facing down at nine o'clock and your hand on her wrist providing resistance. She'll have no strength against you pushing the ball but when done with the hand on the triceps and pulling down the difference in strength is amazing.
Dukhunt,
Did Willy's explanation help? Based on the video above, I got the feel that she was muscling the motion rather than allowing whip to happen. Like Willy advised, pull the ball around and down into release with a loose, lower arm. The ball will be in a trailing, or lagged position. As the upper arm pauses (or locks) at the ribs, the lower arm will whip and as it does so, the hand/ball/forearm will rotate from palm up to almost a palm down finish. The trick is staying loose and allowing the ball to whip out of the hand.
Let us know if that helps,
Ken
Edit: After reviewing the video to the end, she looked much better in the last few... For whatever reason, I only watched the first couple throws in slow-mo before posting.