Dave, if you look real close on the out side of the riser there is a very small hole you have to get a punch that is small and long enought to go all the way to the latch pin and gently drive the pin through the rib, BE very carefull the sides of the rib is very thin and will break if you are not Carefull, the pin will come out the other side from where your punch is.
never had a problem with the spring, just give it a little tug and it should come out.
Hope this helps Harold