[exim] rewrite incorrect date headers from email clients

How I do to rewrite the date header from email clients in exim4 config
so it are replaced with the server date/time?

The problem is that some clients and software are submitting an
incorrect date header (like 1 jan 1960) causing the email to be
delivered to the bottom of user's clients and sometimes sorted as spam
due to the incorrect date.

So I would want to replace the incorrect header with an correct one
fetched from the server time.
How can this be accomplished?