On the power steering reservoir cap you will see CHF 11S, pick it up from the dealer or parts store, cheapest for me is the VW dealership $23.95.
Instead of the banjo bolt I use the motive bleeder bottle, put the rubber tube into the reservoir, squeeze the bottle, plug the bottle's vent hole with your finger (small air tube on top of the bleeder bottle cap) stop squeezing the bottle and let the bottle fill up with fluid, no mess, splash or spraying hydraulic fluid.
Fill reservoir to max line, put cap on, start car, turn wheels lock to lock (while rolling to reduce pressure on system) and repeat using bleeder bottle.
Used the same bleeder bottle trick on the brake fluid reservoir when flushing the brake lines.
