How do I replace cracked vinyl strips on aluminum windows panes?

I have aluminum windows with 8 panes and the vinyl stripping that is around each side of each of the 8 panes is cracked, fading and pulling away as a result of heat and sun. I want to have them replaced but don't know if they should just be snapped in with no adhesive or should have a bead of caulk under them to make sure they stay in place. I think if the gl pane were to be broken later on, those vinyl strips would have to come off to get at the gl. I'll keep extra to replace those strips if needed. Can anyone help with this dilemma? I'd hate to pay to have it done only to have it become a problem again. Thank you.