Basically command line backend means when you press the button it executes a command as if you would have entered it at the shell on the n810.

So it refers to the command line on your n810, which means that in your case you would need some sort of client on the n810 who sends commands to your windows machine.

I neither use nor like windows but the very least you can do is use a workaround by installing a small webserver with php on your HTPC, run a php script there which takes some arguments and then executes the commandline client to send the IR commands.
That's basically what I do for everything I want to control and that hasn't a web or client/server interface.