I have updated the YASMP MineCraft server to 1.6.2! Tell your friends that we are updated! As for horses on this map, well this map was made before 1.6, so you will have to travel around and hopefully land on a new chunk that no one has been to before, you will be able to get horses from those spots far off into the map. Horses are enabled everywhere on the private map already.
I have also unbanned over 100+ people (who got banned for swearing or server hating, not advertising), so if you were banned for that, now you are welcome to come back!! When I get a chance, I might also check if donators have any current bans, and will most likely unban them too.