If I work around the problems in 183371 and 180751 I'm able to get a KDE popup window to come up when I plugin my Canon Powershot S40. However, the default popup uses the system:/ kioslave to access the camera contents. This doesn't work. The contents all show up as files, even though DCIM and TRASH should be folders. So both media:/camera and system:/media/camera are broken. camera://Canon PowerShot S40@[usb:]/ works as it should though, allowing me to browse the contents correctly. So somehow the system:/ or media:/ kioslave wrapper around camera:/ is broken.
Fixed in FC6.