Export to ics file with retaining spaces

[Dieter Faulbaum]

I normally use this hook:
before-save-hook (delete-trailing-whitespace time-stamp 
copyright-update)

But this is not a good idea, if I use org-icalendar-export-to-ics,
because the spaces at line ends are significant in an ics file.

There is only a org-icalendar-after-save-hook
(and not a org-icalendar-before-save-hook).

Any elegant idea to retain the spaces
(without customizing the before-save-hook for this)?

Thanks for any help