You were right.
I recently posted this information to comp.arch.embedded but couldnt log in here, but now I can for some reason.
I obtained an old ISA SMC WD800 network card with links to enable the 28 pin boot eprom. It should work on almost soft configurable cards like the 3com 589 series as long as you use the setup utility to enable the eprom.
I then plugged in a 32 pin socket into the 28 pin socket with the top 4 pins overhanging the top of the 28 pin socket.
I soldered a wire to pin 32 of the top socket and plugged it into pin 28 of the bottom socket - this is +5v.
I soldered a wire from pin 31 of the 32 pin socket and had to solder this to the edge connector finger B11, the /wr pin.
You can view the edge connector pinout at http://www.techfest.com/hardware/bus/isa.htm#6.0
Then plug the DOC into the 32pin socket, and plug the card into the PC. If you are to do a lot fo pulgging in and out, you could use a ZIF socket on a short ribbon cable to make insertion and removal easier.
I sued the freedos CDROM boot disk and burned the various DOC images for the webplayer around onto a CDROM with the M-Sys DOS programming tools. That way it doesnt matter what OS you use, you can always access the DOC.
A similar approach might work with ISA network cards but I dunno.