Heres how to do it. (bear with me) You have to take the sight ladder out. On the Romanian it has a pin holding it in, this needs to be cut. Take a hack saw and carefuly cut that pin, or you may be able to tap it out (mine was froze and had to be cut). Then slide the lader out of the groves. Put the leaf back and that little dimple needs to go into the hole at the bottom the leaf spring will need to be knocked back towards the reciever (there is a grove back there you may not notice it but its there)to hold it in. I use a phillips screwdriver and a hammer to knock it back then you need to press down on the front of the leaf and slide the ladder over it and back into the recess that lets it swivel up and down.
What ever you do-- DO NOT loose the spring.Everyone is out and I had to make my own when this happend to me.
zanthope, I wish you the best of luck. I had to do this and spent many fustrated hours figuring out how to do this. Let me know how it goes.