How to glitch under Station in Ghost Recon 2

How to glitch under the Station map in GRAW 2. These glitches only take 1 person and they are very easy to do. All you have to do is, first while fully standing up, clamber on top of a ledge, second push back on the analog stick kinda slow until your body is half way off the ledge and at this point there will be the option to clamber even though your still kinda on the ledge. Once you clamber again just push back on the analog stick and you will eventually fall right through the map. Sorry this is kinda hard to explain so it may take a few tries but just messing around with it and you'll get it.