One thing i wish i would have noticed the first time i did this:
The stem (7-shaped thing) has a slightly smaller clamping area somewhere. From your pictures, it looks like the front on yours. Keep that towards the inside of the bends on your bars. If it gets hard and starts to drag along the bars, you're doing it incorrectly. I mucked up a nice Cinelli bar forcing it through the stem and was able to slide it right back on, proving myself stupid.