ScriptAction Set CustomFieldValue to already have CustomField Value

i want to set CustomFieldValue when comment the ticket.

i try to use below pages ScripActions.

http://requesttracker.wikia.com/wiki/DefaultCustomFieldValue

it work well when CustomFieldValue is Empty.
However, when CustomFieldValue have Value, it dose not work.

i’m using RT 3.8.8

below ScripActions is using now.

Custom action cleanup code:

my $CFName = ‘CustomerStatus’;
my $DefaultValue = ‘Closed’;
my $RecTransaction = 1;

unless( $self->TicketObj->FirstCustomFieldValue( $CFName ) ) {
my( $st, $msg ) = $self->TicketObj->AddCustomFieldValue(
Field => $CFName,
Value => $DefaultValue,
RecordTransaction => $RecTransaction );
unless( $st ) {
$RT::Logger->warning( “Couldn’t set $DefaultValue as value for CF
$CFName:”. $msg );
return undef;
}
}
return 1;

Does anyone know the way which i want ?

Appreciate the help - Ryo

Ryo Ogata ( ryo.ogata@gmail.com )