I coach our developmental team. I have quite a few kids with femoral anteversion and it does show up REALLY well on beam..!
I have several exercises I give them as well as of course reminders on form when we practice. In my experience, the exercises and stretches help most kids but not all. In fact this is a good reminder, I need to print out another set for one of my newer kids..
If it was my kid, I would ask her coach for suggestions on exercises. I would ask (her primary physician) about a good PT to get her evaluated. One of my DDs had a hip injury that resulted in imbalances and compensation issues, nothing that would have been noticed in the average kid but she's a ballet dancer and it was impacting her training.
But, I would start with her coach. Probably it's something they have already noticed and can give you suggestions for!