http://bugs.winehq.org/show_bug.cgi?id=27996
--- Comment #10 from zoroaster zoroaster@inode.at 2012-10-14 18:03:32 CDT --- Tested Oblivion with Wine 1.5.15 on OSX 10.8.2.
This bug seems to be fixed. Now also builtin works (though in Wine 1.4.1 native override did not improve anything).
Also http://bugs.winehq.org/show_bug.cgi?id=11795 seems to be fixed now for OSX.