Ok well i accidentally discovered this when i got bumped off the edge. But you can also purposely jump off the bump onto the ledge. (Since i got banned from CA i don't have any good screenshots).
On bravo side outside the building you should see a piece of metal poking out.
You sprint and jump at that piece of metal.
You have to curve in quickly and don't run any more(or you'll run though the pillar)
It works for me 1/2 the time