As I said, porting this to other nuvis is not easy, as the overall GUI architecture style could be very different. For example, some nuvis use boost signals, some not.
Also nuviCam has a very complicated getWarningTimeout. I guess they have implemented some storage engine for such firmware settings.
Also it should be possible to set the warning timeout via UpdateDeviceConfig.xml, but on my nuviCam there are additional conditions that have to be satisfied and I didn't have time to fix them all.