i've found another bug in the services_captiveportal.php file:
if i enter bandwith limits and hit save, they are not saved, and the fields stay blank. i'm using
firefox 0.9something and i've figrued out that the missing name="" property of those input fields
leads to that problem. so please just add name="bwauthmacdn" and whatever else those field names
are, if i do so, then it works, i've tried it out.