I have a Thinkpad X230 with a X220 Korean keyboard swap.
Connecting to the X230 via Bluetooth is an Apple Wireless Korean keyboard.
Connecting to the X230 via USB on a Thinkpad Dock is a Das Keyboard Model S Mac Edition Mechanical Keyboard,
X230 travels with me as my main portable and I use the onboard keyboard with the keyboard set to one of the IBM Thinkpad layouts. Everything functions as expected, regular keys and Fn key combos behave as labeled.
When I come home, I plop it into the Dock which connects it to all of the peripherals I have set up on that home setup, which includes the Das Mac keyboard. Separate from the dock, the unit connects to the Apple Wireless KRN keyboard. And because the unit is plugged into the dock, I lose access to the onboard Thinkpad keyboard, leaving me the two Apple keyboards.
How do I switch between these two different keyboard layouts on different physical layouts? The keyboard settings seem to assume that I will always be using one physical keyboard while switching between various different layouts, while the possibility that the use will have different physical keyboards with different layouts seems to be precluded.
The reason that this is important is because of the various different Fn but more importantly, the location and function of Alt, Super, Meta, Ctrl and Fn keys.