I see Addictive Drums as a stand alone, but I cannot get it to show up inside of X3. Any ideas?

I had the same situation.  I downloaded the install instructions for AD, and it had the web address for AD which allows you to install the stand alone version (which shows up in X3).  Just use the product key which should be in your CW account and activate AD and you're good to go.  Hope this helps.

I still cannot see AD within SONAR.
 
I can launch AD as a stand alone, but I cannot see it in any of my lists from within SONAR. I went through the install process. When I login to my XLN account, I see indicators that everything is installed and registered.
 
This is getting a bit frustrating. Maybe there is a certain folder I should include in VST scanning? Any ideas?
 

FWIW
 
I just checked in Sonar and on my disk drive.
 
AD shows up in Sonar in the browser, under the "instruments" tab, in the vst2 directory. 
 
I checked on my disk and the DLL is in C:\Program Files (x86)\Cakewalk\Vstplugins
 
You could force a re-scan of vst. 
 
Although it may not be the same issue, you could try this: http://www.cakewalk.com/Support/kb/reader.aspx/2007013315
 
I hope you get it sorted
 
--edit--
I am trying out AD and noticed it said it was 64 bit. The vst path I posted above would suggest it is 32 bit. Well it also should install a 64 bit dll in the same path (just remove the (x86) part). 

When you installed there should have been a prompt of where to put the .dll file. Like he said above. Check your folder. If it's not there you could copy the .dll in the stand alone version and paste it into the VST plugins folder where your other plugs are. Then re-scan and you should see it on the list.

I have had some instances where they didn't show until I re-started my computer.

I see what happened. I had the scan pointing to a JBridge folder just underneath the default location. I got rid of the JBridge folder since I don't use that anymore. I put the correct path and re-scanned it and I can now see AD.
 
But... is has a (32) next to in in my instrument list. Is this being used as a 32 bit rather than 64? Is this ok?