Those two signals are only intended to work with os.kill -- they are specific to the GenerateConsoleCtrlEvent function in Modules/posixmodule.c. I'll have to change the documentation to note that.

If you want to send those events to other processes, have a look at os.kill and some example usage in Lib/test/test_os.py and Lib/test/win_console_handler.py. This also needs better documentation.