I've installed Addictive Drums however I do not see this anywhere in my soft synth inst listing. I have run the vst scan, and restarted x3  and still nothing I have also added the target folder to the vst scan list. What am I doing wrong?

Welcome to the forum.
Are you running a 32 or 64 bit OS and SONAR version? Have you installed the respective bit version of AD? 32 bit plugins are in a VST folder with addition (x86). That's the only thing that pops in my mind right away.

Hi zimarm5,
There has been some talk of the new VST's not showing up after the install, in particular Celemony. I had to rescan plugins twice before Melodyne showed up as an ARA plugin. Try a rescan from the preferences menu after a reboot.
Let us know how you go.

Running 64 bit..both is & sonar..I do believe i installed the 64 bit ver of AD. funny thing is I installed it and it shows the stand alone Addictive Drums and not the plugin

I have also scaned rescaned..directed to scan to the folder with AD.restarted the computer and software a few times with no luck yet..I guess the next thing is to uninstall it (AD) and start all over again

Check whether AD shows up in Plugin Manager.
 

Does not show in plugin manager...

Does not show in plugin manager...

OK, if it's not displaying in Plugin Manager then it's not being found for some reason.   If you know where your other 64bit plugins are located I would first check for the AD .dll file there. Standalone apps are often separate from the plugin versions. 
 
Also, it's doubtful, but you can confirm that AD isn't on the Excluded list - there's an option for this in the Plugin Manager UI.
 

By default AD installs under Program Files\Steinberg\\\\\ check there for the .dll then either move it to where sonar is scanning or add that folder to sonars scan paths.