Thanks, but the above solution doesn't work.
I have tried before a somewhat different version of the [warning] section in sys.txt. Now I tried yours. With the txt file inserted in its place, of course. Same result: nothing.
By the way, by default there is a sys.txt on the card, but it's empty. I think there is another one in the machine. But that one i can't access.
It may be a license issue, seeing that they're offering the functionality as a paid extra. But I already have a subscription with another provider. I'm paying half of what NNG is asking, and I get my radar warnings on SEVERAL other devices.
So... any other ideas?