Hi Ferry !
Well, the Ken Mitchell panel is the simple folder type panel. What it means ?
For first, unzip it to a temporary location. It will contain several folders, like docs, gauges, panel and sound. The files in these folders should manually copy to the correct folder and you are ready...not to mention these all are written inside the README.txt

So:
Docs folder goes to FS2004\Aircraft\ehm_a330v2\Panel\
Files in Gauges go to FS2004\Gauges
Files in Panel go to FS2004\Aircraft\ehm_a330v2\Panel overwrite mode !
Files in Sound go to FS2004\Sound.
And you are ready
