As far as manga goes that episode seems to be filler episode. And filler episodes according to laws of anime dont count.Episode 232 The Girls Get Together...
When she asks Neji to train her, over time she developes more and you see her use the Gentle Step Twin Lion Fist...
It doesn't say it in words, but if she didnt train with Neji, she never would have developed the technique...
Afterall filler episodes are to let hte manga get ahead of the anime.
Hinata learned in Naruto part this technique:
But it was filler episode, and she has never used the technique in manga.
herefor this training session with Neji never happened. Though it's logical that she may have trained with Neji though
