there is a way that is a bit easier to do this. id record it but dont have recorder. first when u see him jump box to box then on to the sign ledge, just go through the building window and fall on to the ledge of the sign avoiding the hard strafe jump. second, u see him on the sign ledge then he jumps on the box. u can also do a easier strafe off the sign ledge to the box and keep tappin X and u can pull yourself up on to the box. just like when ur jumping over a box or wall the X button appears, well same here. the rest is the same