I just took the PC-9A out for a quick flight in P3Dv4.5 and pretty much everything seems to work fine, including the
Load Manager. The only problem was I couldn't get the two display screens to display. Maybe I just couldn't figure
out how to turn them on, but I seem to recall this was also a problem in FSX. In any case, all the other gauges seemed
to be working fine, so I didn't have any problems flying the plane.
Of course, there was the usual no vc click sounds, but that never particularly bothers me.
I have my Iris PC-9A installed in an outboard .xml folder, so install location in P3Dv4 doesn't seem to be critical. Are you
sure you've copied everything over?
Also, what date is your version, or which version do you have? I've got two version, one a "Pro" version which I purchased
back in 2010, another is a "Training" version which I purchased in 2015 (I can't recall why I re-purchased the newer version).
In nay case, it was the newer "Training" version I just took up.
-Rob