You should have installed DropBox and
IITNConverter.
If you have never saved a route as favorite in Sygic, you should first save a route as favorite, before continuing.
In Sygic, setup DropBox and log into your DropBox.
Plan a route using Kurviger and export it as Gpx-file using the route option and additional waypoints.
You have to convert the Gpx-file using ITNconverter to the .itf format (Sygic GPS Navigation 13,14,15,16).
In DropBox go to Apps -> Sygic All regions -> res -> itinerary and copy your route to that path.
Use your iPad or iPhone and open Sygic.
On the top right next to "Search", you have to click on the small flag.
You will see a menu, choose favorites.
The route should be listed there.
Important: unfortunately, the route will not be displayed by the saved name.
There will be either a duplicated route or the route will be named by the start or end point of your route.
Thanks to Achim for providing these instructions.