u7i7 on "[Plugin: Contact Form 7] A filter cannot be worked."

Hi together,

I would like to change an address according to a choice.
so, I added the following function to function.php.

----
add_filter('wpcf7_special_mail_tags', 'my_special_mail_tags',10,2);
function my_special_mail_tags($output, $name){
$output .= "****1@***.**";
return $output;
}
----

But, it also seems that this does not work well and it is not called.
Can you add_filter well?

http://wordpress.org/extend/plugins/contact-form-7/