Pentagon softsynth won't load in X3b.
Granted, it was the latest/greatest softsynth, but still, I wanted to keep it.
Can anyone else confirm this?

I have rgc-Pentagon working in X3. Direct X on a x64 on W8. Its just still there from all the previous versions of Sonar. 

Isn't Pentagon one of the synths that requires administrative privileges?

Penatagon is still there.  Try running in admin mode and rescanning

Ah, there's that Admin mode thing again . . . this might be my main problem.
Hmm. seems to work now - but why is my install not defaulting me to admin? I ran the install off the downloaded files, apparently I installed with just a double click(??).
 
Ouch, this has been a hassle.

Yeah, I always launch sonar in admin mode. Right click the icon, select properties and check the box to launch as admin.

As soon as  iinstall a new version of sonar, I go into the properties of the .exe file and change settings to "always run as admin.  Unless Cakewalk gets overrun by hackers that send out trojan files in their software, I doubt there is much danger in having Sonar run as admin all the time.  It saves me on going through doing it manually for every plugin that requires it.
 
and seriously, if this is considered "a hassle" I can't imagine how you react to serious issues.

Pentagon is a right royal pain. I reinstalled it and now it no longer associates with older projects, rendering those synth lines useless. I had it as a key sound in a track and had to go back to the drawing board. Totally frustrating.
 

I had a problem getting Pentagon to run when I upgraded from X1 to X2.
 
Running it as Admin cured the problem, and it [the problem] hasn't re-appeared when going from X2 to X3
 
Go figure.