Not sure if it was an issue in older versions, but in v1.7.3 it is working
use this in rich text:
[antispam]your email[/antispam]
put this in functions.php
function protect_email_shortcode($atts, $content = null) {
$email = antispambot($content);
return '<a href="mailto:' . $email . '">' . $email . '</a>';
}
add_shortcode('antispam', 'protect_email_shortcode');