You can access it if you put it in the FX bin of a track.
 
This is bizarre. I think this goes for all synths. Though it seems you can still write the automation by adjusting parameters on the fly you won't be able to adjust them afterwards.
 
This bugs me.

In X2 the automation for Addictive Drums is in the first audio track. At least that is where I found it when opening the edit filter to automation > Addictive Drums 1 after inserting Addictive Drums with "MIDI Source" and "All Synth Outputs: Stereo" checked.

I don't use all the audio tracks so the unused were deleted.
 
Is there a way to fix this after the fact?

The track assignment happens when the synth is inserted. There is a drop down near the bottom of Insert Soft Synth Options dialog controlling which track hosts the automation. Since the track hosting the automation is gone, I believe a new instance of the synth would need to be created.

Thanks for your help Scook. I was able to resolve my issue tonally.
 
I am mixing a track where two toms play instead of the hi hat and that mixed with the BD and Bass was way to muddy. I was able to fix the problem with better EQ and better panning on the toms. I was going to pan the toms wide and automate them back in when needed. If I have to reset everything, I've bookmarked that link you provided.
 
I appreciate the help!

The link is nothing more than the help page for the "Insert Soft Synths Options" dialog. It can be displayed anytime the dialog is on screen. It would be possible to use the existing tracks by inserting a new instance of AD, maybe assign the automation to the AD MIDI track then copy the MIDI data to the new AD instance and point the old audio tracks to the new instance. Archive all the unused tracks. When satisfied everything is wired up right, remove the unused tracks.

That's an excellent idea.