download and use the .imo file from this thread:
https://forum.team-mediaportal.com/general-support-51/imon-pad-remote-configuration-2299/index2.html
Select keyboard use on default for the Pad on the Imon Remote.
All the buttons of the IMON Pad should work properly with Mediaportal then....
After that add a new device in the Harmony configuration tool.
I think i found the IMON Pad under PC Devices....
Then you just have to map a few more buttons from the original Remote.
Add an new activity for watching TV. There you can specify that the Harmony controls the volume through the amp.
I also added a button in the Harmony Display for switching to mouse and keyboard and left and right click.
It's that easy? what about plugins in MP Config, not needed, just this .imo file?