[support] modify the welcome message for some condition [hook_mail_alter]

[Aldo Martinez Selleras]

with hook_mail_alter i do this

function bmg_mail_alter(&$mailkey, &$to, &$subject, &$body, &$from, 
&$headers){
		if ($mailkey == 'user-register-welcome'){
			$body = _user_mail_text('bmg_welcome_body');
		}
}

and the message sent it's the mine, but with empty variables, why?

!username,

MUCHAS GRACIAS POR SU REGISTRO EN !site. You may now log in to 
!login_uri using the following username and password:

username: !username
password: !password

the vars are empty, why??