Has anyone gotten the armor on the billboard that's opposite your Broker safe-house? The one south of the Comrade's bar. It's a yellow billboard. http://faqs.ign.com/articles/875/875341p1.html
It's no. 13 here. I find it incredible how Niko can do all sorts of things but climb down a building, not so much. It's usually a clunky leap of faith and hope you don't die on the way down.