Zaino will bond to the paint, but will not bond to the wax.
The Zaino directions are very clear that there is no advantage to applying Zaino over wax, as it will just come off when the wax comes off.
On one car I used to have, I did not get all the wax off first, and my Zaino protection kept failing after 4 or 5 weeks or so. Eventually I washed it with Dawn real well and applied Zaino, and from then on it kept the water beading for about 4 or 5 months, parked outside.