[O] Add seconds field in custom time stamps

[Nicolas Bercher]

Hi,

I'm quite an emacs newbie but I'm using org-mode since
2 two years.

I'd like to get a higher resolution in time stamps by
adding "seconds" field (%S ?), to obtain something like
this:

  <2013-05-15 Wed 14:18:55>

or

  [2013-05-15 Wed 14:18:55]

But it seems not easy and might confuse, for example,
the rendering of dates within the Agenda (C-a a a).

I've tried to play around with org-time-stamp-custom-formats
without success.

Any pointer or something to start from?

Thanks,
Nicolas