I have installed illiminable codec and a tug support plugin (actually two: one from Softpointer and another WMP Tag Support Extender 1.4) but albums encoded in OSGG still do not show up in WMP's library.

I haven't used WMP for ages but I believe that one thing is having Directshow level compatibility and another, very different is having native WMP compatibility. I believe there's no easy way to make WMP recognize and catalog vorbis as a native format, It only relies in DS for decoding, ignoring everything else.
I may be wrong, but I think the situation is not going to get any better. You are out of luck, my friend.
You should use other players if you want library support for ogg vorbis.

Ogg is not very suitable for WMP, you should try Foobar2000 instead.