fontutils: what about ligatures?

[Markus Uhlmann]

hi.

i am using the fontutils package for converting a self-made metafont
to type1 scalable (e.g. for use in pdf documents). i use the following
sequence of commands (suppose that i have a metafont source
'nn20.mf'): 

#!/bin/sh
echo '-----------creating GF with high resolution (proof mode)-----------'
mf nn20
#
echo '-----------creating TFM--------------------------------------------'
mf '\mode=ljfour' input nn20
#
echo '-----------creating BZR outline------------------------------------'
/home.local/fontutils/bin/limn -verbose nn20.2602
#
echo '-----------wrting to adobe GSF (=PFA) format-----------------------'
/home.local/fontutils/bin/bzrto -pstype1 -ps-font-info FontName:nn20 -verbose 
-output-file nn20.gsf nn20
#

what i get looks okay for starters. however, ligatures disappear from
a typeset text (e.g. the classical 'ligtable "f": "i"=:oct"014",
"f"=:oct"013"').

i would be glad about any suggestions/advice/pointers.
thanx!

markus uhlmann