Casting does not change an object. You must copy the relevant value(s) from
the object returned into a new DateTimePlus. Since DateTime's constructor
takes only a string, and I assume it won't accept your format directly,
you're better off converting the string into a Unix timestamp and creating a
new object from that. However, I leave that optimization to you. The
following code is sufficient:
$plus = new DateTimePlus();
$plus.setTimestamp(parent::createFromFormat("H.i d.m.Y",
$string).getTimestamp());
return $plus;
David
