Add comment_meta to wp_comment_reply

I have added some custom meta data for all my comments. I show this meta data in the backend. However, I would like to be able to insert metadata in the wp_comment_reply editor as well:

Screenshot: http://i.stack.imgur.com/MoFWo.jpg

I thought I could use a wp_comment_reply filter for this, but I can’t get it to work. Does anyone have an idea?

This is what I tried:

function wporg_more_comments( $content ) {
    	echo '123';
        return $content;
    }

    add_filter( 'wp_comment_reply', 'wporg_more_comments', 5, 1 );