F-Spot stopped displaying thumbnail for RAW photos

[Jenner Fusari <jenner neurotix com>]

Hi all,
in my Debian (mixed testing/unstable) F-Spot (now 0.4.1, the behaviour 
started with the last 0.3.5 passed in Debian unstable) stopped 
displaying the thumbnail for RAW file (got Fuji S5500... so .raf files).
It imports images correctly (but even the import viewport never show the 
RAW files), it shows the image while in fullscreen or in edit mode, it 
knows it's a RAW file (because can open it in UFRaw) but there's no way 
to get the thumbnail even by regenerating them. Exiftool say the 
thumbnail (in the exif data) is present...

Does this happened to others? Can I fix it in some way? My F-Spot is so 
sad now: it's a land of empty white cells... :(

Thanks to anyone can help me.

Bye
   Jenner