Thinning Pony's Mane , any help please

[han4]

Her mane is very thick and is hard to plait nicely and hard to maintain. What can i do to thin my pony's mane without taking any or little length off?
Is a solo-comb the only option? she is not happy with pulling her mane either.

 

[be positive]

I use a rake, it thins without shortening, I dont like the solo combs.

 

[maree t]

i bought a thinning comb in the local tackshop. It is literally a comb with a blade in the middle. fairly easy to use