My guess is that the other steering wheel provides the vibration function to alert you. Some of this stuff is embedded in the base code, some relies on a special control module. Retrofitting bits can sometimes be quite complicated if the wiring is not there to support it. BMW does not generally supply one harness...it is built with only the wires and connectors needed for the options as ordered in most cases. This saves them some money, but also means replacement can get costly and somewhat time consuming, as it needs to be built specially, rather than one common part off the shelf. MOstly gone are the days when a harness might have lots of unused connectors, just waiting to plug in an option should you decide to do it later. It's also possible that the camera or it's lens and housing may differ.
If someone does figure out an easy way, it would be useful, I'm not holding my breath.