smrobs, I personally did learn to ride english myself. So I started with whatever (sitting (aka bouncing) of course), and then posting just "clicked there" one day. But from what I see at the lessons the better way to go is to start teaching the posting one. in fact it's HARD to do sitting trot correctly. It requires a good balance and really good core muscles/leg (I'm not talking about just bouncing on horse back most beginners start with, but actual riding).
"Life isn't about waiting for the storm to pass: it's about learning to dance in the rain..."
"When we are no longer able to change a situation - we are challenged to change ourselves."
"How people treat you is their karma; how you react is yours."