in the webassist/email/templates folder open the tempalte file for you email message.
at the top of the code, find the following block:
$removeBegins = array();
$removeBegins[] = "Security";
you can add the submit button to this array to have it removed from the email message:
$removeBegins = array();
$removeBegins[] = "Security";
$removeBegins[] = "submit";