Shoutbox

Windows Live Messenger has got it's sounds in WMA-format. (For example the sound "online".) Messenger Plus Live doesn't support sounds in WMA-format.  So when I make an own event notification i can't use those sounds.
1. The WMA-sounds doesn't even show up in the folder I'm looking in, even thoung i choose "All Sound Formats"

2. If I write "Online.WMA" and tries to preview the sound, a message apperas "Sorry, this soundfile cannot be preview by messenger plus!"

I've converted all Messenger sounds

I've done that too, but it shouldn't be nessecery. Think about all the userst that don't know how to convert?

Messenger Plus! (all versions) use libsndfile and the LAME codec to play sound files. If memory serves, libsndfile plays numerous uncompressed formats, and LAME deals with MP3 files. Microsoft has the WMA codec somewhat more locked down in terms of people being able to make third-party versions.
libsndfile list of formats
LAME Codec