Kerning doesn't seem to work with TRT direction, in the attached axample
(using the attached font), enabling kerning with TRT direction inserts
positive kern between first kern pair and nothing between the rest (it
should be negative kern). With TLT direction kerning seem to be fine.
Using \kern primitive seems to work fine too.

Regards,
 Khaled

-- 
 Khaled Hosny
 Arabic localiser and member of Arabeyes.org team
 Free font developer