If you do a search on glock talk I think you'll find that someone has installed one of these. So if you pm them I'm sure you will get some helpful advice.diamondmike said:
I usually keep it on me in the car. I have a cheap holster that I put on a leg strap. It clips on and off easily and is better than the glove box. I think Black hawk sells leg straps for $3.
For those times I put it in the glove box I made a copy of the key so I can unlock my glove box quickly. I just set the key on the cup holder when I'm driving. I put the key in the armrest when I'm not.