I "re trained" two horses manes and I did it by braiding them. What worked for me was to braid one baid to the next, split the hair in two and braid that hair to the next one, so that created one big net. It took me ten minutes and her hair from the mane resulted in only one piece.
I was trying to find a picture of it, but couldn`t find it. I kept it like that for about two weeks and wetted the hair every two days or so.
If I find a picture of it I will posted because I don`t know if I am clear, and it sounds complicated but it was very simple.