The Hansgrohe unit I put in had a similar system as the one you describe. It worked very well in my case.
They both look like 'male' Velcro, but unlike real Velcro, which is hooks and loops, these are interlocking 'sticks'.
When I pressed down on it, it took a little effort to make it work, and I heard an obvious 'click', with the material on the Hansgrohe.
The important thing to keep in mind is the depth at which you set the body from the tile face. Perhaps it is not quite close enough to allow for proper contact.
I did, by the way, use clear Silicone caulk along the top edge of the finish escutcheon plate. I masked it off prior to sealing, so the caulk line is less than 1/16" wide, so hardly visible.