Brigitte - Sorry for the delay. The bathroom was inaccessible until today, so here are some pictures. I basically took one of the "over the wall" hooks, cut off the hook part, and glued on a wall-mount shower head holder I bought for $1 at the Habitat surplus store. They had a ton there, but that was a few years ago. I searched a bit online to find it, and came up short.
This one looks close, but it is different, and obviously, the hole has to be large enough to accommodate the larger diameter wand on the Oxygenics head.
What's kinda nice about this holder is that it can hold the head in several positions. I'm 6'2", so I only use the position that makes it completely vertical. But my wife is a bit shorter, and sometimes uses the tilted position.
Note that I believe CampingWorld sold a holder specifically for this shower head when I bought mine, but the reviews weren't particularly positive. But it may be worth a shot if you're coming up short.
Dave