[need help] minor mode buffer local keymap question

OK, I'm trying to have a buffer-local keymap variable which is used by add-minor-mode. I tried passing the symbol as the keymap argument, but this does not seem to work. Looking at keymap.c, get_relevant_minor_maps calls minor_mode_keymap_predicate which calls get_keymap. Get_keymap seems to indicate that it will dereference through any symbols, but I don't see how this works... it seems to be looking through function slots. Can anyone clue me in as to the right way to do this? The prize is that ediff-minor-mode (which came to me in a dream this weekend and will allow one to ignore the control frame and work from the ediff buffers themselves) should work once this is resolved. thanks greg