I'm not sure how I setup my Harmony, it is already a long time agoI think I've used the same as you are referring to....
I have installed the Imon software, so I can not say whether that is really needed.
You seem to be following correctly, install IRSS 1.4.2.2391 (the latest version as far as I know) and select Imon in the IRSS config (follow the steps as on my website). Within MP Config don't select a remote, but in the plugin section you have to configure the IRSS plugin (follow my website again).
Good luck, and let me know when you encounter any problems.
By the way: I am still struggling with the standby/resume problem, which I think is caused by IRSS....
Ok, that helps. I will try again tonight when I'm at home. I don't mind that much about standby, I always do it by hand anyway with the power button.
Thanks a lot so far!
Netherlands