bind alt + . in bash vi mode

[alberto fuentes]

I set it to emacs
    set -o emacs
then i saw the function i was looking for was yank-last-arg
    "\e.": yank-last-arg
    "\e_": yank-last-arg

I tried to create it for vi mode with
    set -o vi
    bind -m vi-insert "\e.": yank-last-arg

but it does not work... as a side effect 'a' key stopped working :/

Does anybody knows how to achieve this?

Thanks!