"The .desktop file has the X-Ubuntu-Gettext-Domain=banshee field which should
make Banshee appear in the menu and other applications properly anyway. "
This is the problem, because the .mo file is called banshee-1.mo, not banshee.mo. I just changed /usr/share/applications/banshee-1.desktop to use X-Ubuntu-Gettext-Domain=banshee-1 and the menu item became translated.
"The .desktop file has the X-Ubuntu- Gettext- Domain= banshee field which should
make Banshee appear in the menu and other applications properly anyway. "
This is the problem, because the .mo file is called banshee-1.mo, not banshee.mo. I just changed /usr/share/ applications/ banshee- 1.desktop to use X-Ubuntu- Gettext- Domain= banshee- 1 and the menu item became translated.