org-mode: fontify code blocks natively

I can't get org-mode to fontify code blocks the way it should...I'm using Gnu Emacs 23.3.1 on cygwi开发者_运维问答n and I tried it on same version WinNT. In my init file:

(setq org-src-fontify-natively t)

Then I expect blocks like this to fontified like sql-mode:

#+BEGIN_SRC sql

SELECT * FROM foo;

#+END_SRC

The contents of the block are shown in a different face to normal text, but no keyword highlighting etc. The same goes for other languages. Any ideas?

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My org-mode is too old (6.33x, which ships with my Emacs). This feature requires 7.x. Sorry for the noise.