I agree, I'm certainly not going to air any internal Avid secrets, but I think it fine to have a basic outline of the build process here, for anyone else who is considering building their plugins in AAX form. It sure would have saved me some time : )
So ... what I've learned, for anyone else that may be interested in developing an AAX plugin is ....
You need to:
1 - get approval to join the Avid developers program (developer.digidesign.com).
2 - download the SDK from there, as well as a dev version of pro tools
3 - compile your juce plug (and on windows, put it in the appropriate folder structure, see link in original post)
4 - notice that at this point, your plugin won't load on Pro Tools .... because it is not digitally signed.
5 - send an email to iLok (who does all the piracy protection stuff for Avid), and tell them you need access to the code signing program. They will need to verify that you are actually part of the avid dev program
6 - Go out and buy an iLok2 ($50 at guitar center, and yes, you will have to do this)
7 - sign up with iLok, get an account. Run ProTool and give it your iLok creds. Now you'll realize you don't yet have a license (gah!).
8 - Now you will need to do some things for iLok to get a license. That is kinda internal to their company, so I won't post the process here. Suffice it to say it is tedious and annoying, but doesn't take that long, and doesn't cost anything.
9 - Now you get a developers liscense from Avid, then some ilok liscenses from iLok, then you grab the tutorial on how to digitally sign the code.
10 - Acticate all the liscenses using their iLok manager software (I found this to be kinda hacky ... but it worked eventually)
11 - Then compile the plugin and run some commands using the PaceAP wraptool in terminal to sign the thing, and you're good to go.
That's it! Not as simple as AU or VST, but not too bad ... just takes some time to get the dev liscenses / etc.
Also note, that on windows you need to create a directory structure to house the plugin file (see other AAX posts for that).