code: public void removeMailServer(String hostName, String username) throws SecurityException {
  	checkWriteAccess();
  
  	Element mail = _getRootElement("mail");
  	Element[] children = XMLConfigWebFactory.getChildren(mail, "server");
  	String _hostName, _username;
  	if (children.length > 0) {
  	    for (int i = 0; i < children.length; i++) {
  		Element el = children[i];
  		_hostName = el.getAttribute("smtp");
  		_username = el.getAttribute("username");
  		if (StringUtil.emptyIfNull(_hostName).equalsIgnoreCase(StringUtil.emptyIfNull(hostName))
  			&& StringUtil.emptyIfNull(_username).equalsIgnoreCase(StringUtil.emptyIfNull(username))) {
  		    mail.removeChild(children[i]);
  		}
  	    }
  	}
      }
docs: removes a mailserver from system
  
  @param hostName
  @throws SecurityException