the easiest is to just hold +fwd and +right and wallrun along the righthand side, then you jump, and only hold +fwd while you move the mouse very fast 180 and jump again.
or you can circle right then circle left (or left, then right) at almost any point of the stairs and you'll be able to get to ra
I see alot of people executing the last jump using +forward only. For me using +left or +right (depending which side you are on) gives the best result, a more responsive jump than the +forward one.