Hey Birdy, I've done everything as well, I've been trying for months and I cant preveiw through VLC either, it defaults for everything else I want to do outside LW but not while Im in it...
I have even installed the codecs for WMP and can veiw completed downloads through it, but when it comes to previewing incompletes and stuff thats still downloading it wont work either...
Go figure lol.....
Got any clues as to why....