Trying to bind <ESC> to keysequence "öö" in bash vi mode

Question

I am trying to use the german umlaut "ö" in a sequence "öö" as a binding for ESC. Having the following in my .inputrc does the job with "jj" instead of "öö"; however, when changing "jj" to "öö", it does not work (i.e., does not have any effect at all).

$if mode=vi
    set keymap vi-command
    "jj": vi-insertion-mode
    set keymap vi-insert
    "jj": vi-movement-mode
$endif

I am using cygwin on Windows 7; GNU bash, Version 4.1.10(4)-release (i686-pc-cygwin)

Any help would be highly appreciated!