Holy MOLY I have to bow down and show some major respect! The fact you are aware of all the necessary registry settings is insane (literally LOL!).
Unfortunately, this did not solve my problem. It did, however, produce the following result:
http://cid-04ff010431edad04.skydrive.live.com/sel...SharingFolders.png
So SOMETHING is happening, just not the expected result. This is ALL very strange, considering that I'm installing everything on a fresh install on VistaSP1 on a 64bit machine. Weird, mang...