Add keywords in org comments

Dear all,

  I have used org mode as agenda for several months and was really
impressed by its great features.  Now, I want to port my notes from muse
mode to org mode, in which I recorded many emacs-lisp, c/c++, ruby
snippets.

  In my color theme(color-theme-dark-laptop), the comments are red.
It's OK for coding, since comments are important and worth reading.
While in org mode, #+BEGIN_SRC/#+END_SRC are only code block indicators
and not worth reading.  I wish they could be in dim colors and don't
pain my eyes. (In fact, I wish the whole embedded code block could be in
a dim color if it's possible.)  However, I don't want to change all
comments in org mode, because I want others of them, such as #+TITLE, in
a bright color.

  I used to add some keywords in emacs lisp mode with following codes.
They works.

(font-lock-add-keywords
 'emacs-lisp-mode
 '((";" ("\\<\\(GM\\|NB\\|TODO\\|FIXME\\)\\>"  nil nil
         (0 'font-lock-warning-face t)))))

  But I cannot change face of #+BEGIN_SRC/#+END_SRC with following
codes.  If the first character # is in the column 0,
#+BEGIN_SRC/#+END_SRC is displayed in the default face,
font-lock-comment-face, not my org-embedded-code-face.

(defface org-embedded-code-face