This has already been reported to audacious' developers but the answer was "We just use GtkStatusIcon, so there's not really much we can do. Sorry."

After KDE 4.8.2 > 4.8.3 update there is no audacious tray icon wisible in KDE, although you can use it as well as it was there. So right-click menu works, mouse wheel scroll over works, it takes place between other icons, but the very graphics is not visible.

I removed ~/.config/audacious and checked version 3.2.2 and 3.2.3.

On the provided screen Audacious' icon should be placed between white kmail's icon and yellow psi icon.

Reproducible: Always

Steps to Reproduce:
1. Install audacious
2. Enable tray icon in plugins
Actual Results:  
 Icon takes place in the tray but it's invisible

Expected Results:  
The icon graphics should be visible

It worked in 4.8.2
http://redmine.audacious-media-player.org/issues/121