I installed my camber/caster plates this weekend and ran into this problem. The driver side was a breeze to get back together, but not so with the passenger side.
Yes, you have to pry down on the LCA pretty hard, but that's not really the problem. In my situation, it was more the angle of attack. You need to have the lower ball joint pointing out away from the car. With the control arm lowered, this allows for the highest point of the ball joint (the edge of the top) to be lowered as much as possible. You can then pull the strut and khuckle assembly out just enough for everything to fall into place.
Here's what I found when I had problems with my passenger side. I noticed my driver side ball joint was firm and would hold into place where ever you moved it. My passenger side was not like this. It move around easly, but when you removed pressure from it, it would return to it's center. So I was not able to get the edge of the ball joint as low as possible.
What did I do? I got my 9 year old daughter, who was out there with me watching everything I did and asking questions, to move the ball joint into place for me. Once it was in place, I slowly released on the LCA just enough to catch the knuckle. I then told her to remove her hand and I took it from there.
Problem I had then was getting the stem of the ball joint to maintain the proper angle while traveling through the knuckle! I was pretty tired from fighting with it, so I took a break. I can back out and worked with it some more. I still couldn't get it, so I just started kicking the hell out of it! Still nothing. I then walked away from it for about an hour or so, went back outside and it fell right into place after a few taps on the bottom of the ball joint.