I had similar problems, can't remember all the details. Things to try are mobigen (not calibre like I just typed.) ... are you sure you need kf8 for fonts?
Anyway, I punted and put my font in /mnt/us/fonts and set ENABLE_ALT_FONT(s), and went on with my life.
My font was in extended unicode, so getting it to show up on the kindle involved many, many possible points of failure.
Last edited by shakaote; 02-23-2013 at 04:58 PM.
Reason: brain lapse