Hi, I am having an issue getting Banshee to work with my mp3 player.
The device works fine in the filesystem, AmaroK, Clementine etc.....
I am using Kubuntu 12.04 with backport enabled, with Banshee 2.6.1 from the Banshee ppa.
Does Banshee recognize other "media insertion" events, e.g. when loading a CD?
You're aware that Banshee is a Gnome application and mp3 player support needs some functionality from the Gnome desktop infrastructure (gvfs) - all your working examples are KDE (or at least Qt) apps.
Start banshee from a terminal window with debug output enabled:
banshee --debug
and post the output when you plug in your mp3 player.