I had these side parts recovered so I also had to reinstall the aluminum trim part
I found it rather difficult, you want to get the trim close to the raised part so it looks even, but too close and it won't sit down properly
Here is what I did to get the nails in:
You need to press very evenly or the trim will bend and if it kinks you might not be able to fix it
I marked on the trim with tape so I would know where the nails where, and the part next to the nails
Cover the trim with a thin cloth so it won't scratch
Put a smooth board over the trim, about the size of the trim
Then you can tap on the board to drive the nails in and have even pressure along the trim
Make sure all the nails are straight
But not easy, I spent several hours doing this
it sounds like a nice procedure, but i found that to me the only way was pressing with my thumbs, that was the way to keep the control over the nails, as you mentioned if you bend them they will not recover
disclosure, i have very strong thumbs
note, in these cases i love to use a vice, the advance control with the vice is absolute, but unfortunately the nails are extremely delicate