I've got an E-Class S212 with the NTG 4.5 system,
I've updated the nav to the latest maps (v19), then noticed the lack of camera warnings when using it,
I used the "Mercedes 2013 GPX POI" file downloaded here
GPS POI File - Download Zone (gps-data-team.com), copied to a FAT32-formatted SD card (inside a folder called PersonalPOI) only costs £1 to register. It loads up fine but on my car there is no option for an audio alert, just shows you the camera on the map. But it's better than nothing and I much prefer navigating with the Sat Nav integrated to the car than using my phone, personally.