How do you affix the cradle to the window glass so it doesn't come out?

OK. To further clarify: I am installing the window cradle on the bottom of the passenger door window of my new X1/9 because the old one had rusted away. The rubber attached to the window bottom is still there. What I am trying to find out is if there is some type of adhesive that should be used to keep the window and the cradle from separating when the window is rolled up and down. Anyone?
Lots more work to do besides this but I want it right!
Here is a picture of my new baby the day she arrived!