I have this same problem on a Mac (OS X 10.11.5). I.e., PM finds SDX that were installed to a custom location but not EZX.
I did the entire download, install, authorize process again using PM and that worked fine and the Installation Info tab for each library shows that the Sound Library and MIDI are in Library/Application Support/EZDrummer.
Now if I drag the installed EZX folders from Library/Application Support/EZDrummer/ to my desired custom install location (as described here: https://www.toontrack.com/faq/how-do-i-move-the-sounds-for-ezdrummer-2/ ) PM will then list each EZX library as “Not installed” in the Installation Info tab. In the Superior II/Options screen I can simply browse to the new location of the moved libraries, but PM provides no way of doing that as far as I can see.
