You have to edit the file \administrator\components\com_hikashop\types\user.php and replace your load function by:
Code:
function load($value){
$this->values = array();
$query = 'SELECT user_id, user_cms_id, user_email FROM '.hikashop_table('user');
$db =& JFactory::getDBO();
$db->setQuery($query);
$users = $db->loadObjectList('user_id');
$query = 'SELECT * FROM '.hikashop_table('users',false).' ';
$db->setQuery($query);
$usersCms = $db->loadObjectList();
if(!empty($users)){
foreach($users as $user){
foreach($usersCms as $userCms){
if($userCms->id == $user->user_cms_id)
$this->values[] = JHTML::_('select.option', (int)$user->user_id, $user->user_id . ' ' .$userCms->username );
}
}
}
}
