>> IIRC this only works if you do NOT have the VISUAL env var set.
>> Kinda strange...

>$ set -o emacs
>$ VISUAL=vi; export VISUAL

The trick is to

export VISUAL=vi

in ~/.profile and

set -o emacs

in $ENV (eg ~/.kshrc)

I've used pdksh and various other ksh for many years, though I avoid writing 
scripts that need more than /bin/sh (though on some boxes ksh is the _only_
sane shell), I very rarely notice a difference b/w pdksh and ksh on 
Solaris or HP-UX (though I've not used that for a few years now).

If interested http://www.crufty.net/ftp/pub/unix/configs/etc/ has copies
of a decent? /etc/profile and ksh.* which I've used on lots of flavours
of unix.

--sjg