My method of installation is to put a little bit of 3M yellow snot adhesive on the end, and then tap gently with a piece of 3/4 inch furing strip & a hammer.

I let the 3M adhesive cure a little while to get a skin on it so that I do not have it all over the place.

It works most of the time and they generally do not fall out everytime the hood is closed.

Good luck...it really is a PITA and no one really does a good job of reproducing them IMO.