Currently, it is possible to export your route from your computer in GPX file format. The process is described below:
The menu item "Route" takes you to an administration page of all routes. If you have already created your own routes, they are listed here under "My Routes". Click on the route name or "View route", which will take you to the route overview.
Click on the "Download route as gpx file" icon to open a pop-up window. Go to "Save file" and confirm with "OK". Your file with the GPX data is then saved under your downloads. You can transfer them to your navigation device using a data carrier supported by your navigation device (usually an SD card or USB-Stick).