rc.custom

hello

i think i have to edit the rc.custom, but i do not know how to save 
it.
i found lots of mails in the archive, but no answer.
sorry, i need a first step.

i tried to mount the tomsrtbt.raw file with "-o loop", but my 
kernel does not support minix fs.

that's what i want to do:
place a script on the tomsrtbt-floppy.
the script ...
-makes two directories 
-mounts a harddrive and a nfs-share
-writes an image of the hardrive to the nfs-share (with tar)
or writes the image back to the harddrive

thanks for any hint.

beste gruesse
jochen