Building OSX Bundles for Unity Extensions with External Frameworks

I'm writing an extension to access the some license management software. For Windows, I was able to build a .dll and access the license management functions with no problem. However, when I move to a Mac and build a bundle accessing the same libraries as external frameworks, Unity never loads the bundle, always throwing a System.DllNotFoundException.

I've noticed that when I look at Unity's sample extension project, the bundle shows up as a folder in the project window. All my bundles have a box icon instead of a folder icon.

I've but the bundle in Assets/Plugins, and in the same folder as the executable (which works on Windows), but the bundle is never seen on the Mac.

I've seen this discussed in the forums, but I can't see that anybody's ever figured it out. I'd like to know:

  • What type of Xcode project do I use to build the bundle
  • How do I import the 3rd party libraries (frameworks) into my bundle so that Unity will see them, and
  • Where do I put the bundle?
    • in Assets/Plugins,
    • in the same directory as the executable, or
    • in some mysterious OSX place unknown to people with as much Windows brain damage as myself

The problem was I was building a 64 bit bundle, and Unity wants 32 bit bundles.