Hi,
As jerome said, you need to display the field using the custom field system (with the field class and the "show" function):
<?php $fieldsClass = hikashop_get('class.field');
$fields = $fieldsClass->getFields('frontcomp', $this->row, 'category', 'checkout&task=state');
foreach($fields as $key => $val){
echo $fieldsClass->show($val,$this->row->$key);
} ?>
But normally, custom category fields are already displayed on the listings as long as you turn on the "frontend" setting of the field, so it should not even be necessary.