That is exactly it! Thanks! For reference, here's what I did, and now everything works as a charm:

sub normalize_column_values {
  my $self = shift;
  my $hashref = shift;

  if (exists $hashref->{password}) {
    $hashref->{password} = Digest::MD5::md5_base64($hashref->{password
+});
  }
}
[download]

Thanks!