This is another spot I know. Usually when I hit this spot from the alley you show though, my goal is to jump over the building and land on the street below. And, speaking of the street below, I can once again offer a flashier and more difficult method of reaching your spot (nowhere near as difficult as the "slingshot wallride" though). This stunt can be done on a Ruffian, but I have a MUCH higher success rate on the Bati.
What we're going to do is a quick double bump from the southern, downhill side of the building and backflip onto (or sometimes completely over) the roof.
This is the entrance to the courtyard, the hedge in the middle is what we'll be bumping off of. To get the double bump you'll have to be very precise, as you're aiming for the highest bit of the planter, that small square piece in the center of the pic. Hit anywhere else and you'll crash into the overhang of the wall just past the planter, at best.
The way to do this is to head the the intersection one block south of the building, which is the intersection just north of the LSC, and is in fact the very intersection shown in your first pic. You don't need to go farther, as it's possible to get too much speed for this stunt. From that intersection, simply race up the hill, and try to stay on the center line of the road; it lines you up almost exactly for the double bump. Pull your wheelie after cresting the hill, don't forget to backflip for the extra air, and you'll be landing on the roof in no time. Enjoy!