I tried in initial_values() to
global $activitydate;
print var_dump($activitdyate);
If you're looking for the date of the previous registration, you'll have
to do it differently, because it won't be available (due to the redirect
indeed)
You can create a function like this:
function postAdd($rec)
{
}
in your class. This function is called right after the record was saved.
$rec contains the saved record. So $rec['activitydate'] contains the
date you need.
In that function, you can decide to store the date in the session, by
doing this:
sessionStore("lastsaveddate", $rec["activitydate"]);
Then, in initial_values, when you're going to save a new record, you
could do:
$lastsaveddate = sessionLoad("lastsaveddate");
and put that in the correct variables.
Hope this helps.