DBFORGE add field zerofill

Hi,

I would like to create a table with a field tinyint(2) unsigned zerofill. When I try the statement below column is created but zerofill don't work. 

'month' => array(
                    'type' => 'TINYINT',
                    'constraint' => '2',
                    'unsigned' => TRUE,
                    'zerofill' => TRUE)


Do you have the solution ? Is my syntax correct ?

Thanks