Add values to the list of defined values for the $fieldname.
The @values will replace the old values for the $fieldname. Returned is the LIST of values after modification.
The %options are used to initiate a mailer object via
Mail::Mailer::new(). Then Mail::Mailer::open() is called
with the knowledge collected in this Mail::Send
object.
Be warned: this module implements raw smtp, which means that you have to escape lines which start with a dot, by adding one in front.