Short: … but Windows Vista SP2 16489 ThemeUI.dll, Shsvcs.dll have!
A reader that goes by the name DJxSpeedy was kind enough to smack me in the head and make me look at the two files involved in enabling third-party theme usage. They did change after all. Oops. You can now grab the freshly patched x86 and x64 binaries from the repository.
Thanks for the heads up, man.

[...] Update: Files have changed after all. [...]
hehe thx man for writing my name ;)
But theres 16497 build being distributed now.. When do you plan to release patches for it?
As soon as someone sends the files to me… [name]@withinwindows.com
jj
You can get latest files from here: http://rapidshare.com/files/170648369/6.0.6002.16497_XX.rar
MD5: C92888A086919EF2221F45256300B8D6
I’ll send this as an e-mail to you too.
UxTheme.dll file has not changed again, lol.
Your work is much appreciated Rafael. I hate windows standart themes, and you’re da man who makes me enable new themes.
Cheers