Please help me make a diet for a pony that had laminitis

Thanks very much Peggysue, I always have problems because I don't know what to look for when I'm buying vitamins.

@Super Nova:
He's not obese. Anymore...
Before we bought him he was getting tones of oats (more than some horses that compete) and free choice very quality hay. His hooves weren't trimmed for ages and time to time owners drag him out and sat on him and kick him until he moved. He has 550Ibs and the rider had 190Ibs. He was ridden with awful hooves on roads, which also could be the cause.
But the main cause I think it was wrong food.

What does cushings mean? Sorry, my english is not good :(

Thanks for advices :)

I googled cushings :P
No, he definitely doesn't have this.

Ok looking at his pics he is at a good weight now .. hooves still need work and topline which is where the QUALITY amino acids comes in. Other then that I would leave his diet alone

Soak the hay soak rinse soak rinse