I'm doing a similar thing - trying to get it to install on Longhorn 4053. After using Windows XP compatibility mode the installations seemed to go OK, except WMP was not updated
Another thing you might find useful... If you try right clicking on the inf files and clicking install, some of them will claim they have "not been certified to install on this platform" (or someting like that). Changing the class-guid (or whatever it's called) will make them install OK (at least it seems like they are copying files). I have also tried replacing the main EXE and a few DLL's manually. So far I've succeeded in screwing up my existing install (complains the version is unexpected).