Actually that is the solution you’re looking for. The coordinates given (135, 135) are easy to input, if you set the rotation pivot to the cursor, located at (0,0,0) and then rotate the sun around it (start with the sunlight positioned somewhere along the x-axis, pointing directly at (0,0,0), then input the inclination and then the azimuth.)
However, the inclination should be reduced by 90°, otherwise your sun will change directions during the process. You’ll see what I mean if you do it
Or, as Morio suggested, just calculate the cartesian coordinates, using his formulas. No need for some extra option if you ask me, and the info on the wiki is not wrong either. It does nowhere say, that you should input the coordinates as they are written down there. It’s just a convenient way to make the directions of the sunlight clear, as in real life.