Currently it can not.
It should work fine with KMPH, it doesnt announce your speed as MPH or KMPH, you will have to set RR for international units
In RR config go to the GPS menu, then select international units. This will set your speed to KMPH. As far as setting the speed limits, you may have to make some changes to the entries in you add to the exectble.ini to reflect the speed limit presets you want to use. But the speed zones should work no matter what units you use KMPH or MPH.