YEAY!
I just got the solution (that worked for me, anyway) from a Sony support rep. No PC or VMWare needed.
OK, you've installed Sony eBook Library v3, and Adobe Digital editions, you've set up your acocunts and authorized your computer on both of them, and you've authorized your Reader with the Sony Library application.
You go to the public library ebook download page, either through the Sony Library or just through a bookmark.
You check out a book, and open it in Adobe Digital Editions, which still won't recognize your Reader.
BUT, in the Sony Library app, you can now click "File, Import.." and go find the pdf you downloaded with the Adobe app.
On my Mac, it was in ~/Documents/Digital Editions
Import it, and drag it to your Reader.
The first time you do this, it will ask you to authorize the Reader with your Adobe ID.
Worked like a charm.
