Additional key binding for RefTeX to add new bibliography entry

Question

Nowadays I often insert @Online entries into my bibliography files.

Unfortunately, the RefTeX doesn't have the Online-Entry bound to any key by default.

I tried to add something like

;; I often use the "@Online" entry in my bibliographies.
;; Unfortunately, no key binding was defined by default.  I think C-c
;; C-e C-o would be a good choice and is still unused.
(define-key reftex-mode-map (kbd "C-c C-e C-O") 'bibtex-Online)

Running eval-last-sexp (bound to C-xC-e) gave no error, but said bibtex-Online as expected.

What is my mistake?

EDIT

After having Emacs restarted, the key binding worked, but unfortunately (again!) not in a buffer with a bibliography file! I was working on my LaTeX file and when I tried to insert a new environment by pressing C-cC-e, but instead of asking which environment I was about to insert, Emacs waited for the next keypress an ah voilà, after completing the session with C-o Emacs most happily inserted an template for an Online document (@Online{...}) into my LaTeX buffer. Yet, still, the key binding didn't work in the bibliography buffer :-(

Answer 1

Hurray. I found my mistake.

Instead of

(define-key reftex-mode-map (kbd "C-c C-e C-O") 'bibtex-Online)

one has to write

(define-key bibtex-mode-map (kbd "C-c C-e C-O") 'bibtex-Online)

You have to use bibtex-mode-map, not its brother reftex-mode-map.