WebDAV transfer limit and AD auth

[My1]

hi, we want to use WebDAV over IIS to give the users the ability to get on their documents etc over the internet, and I want to ask whether or not there is a way to limit the transfer per user, like 500MB per month

Also we want to do this over AD authentication, but the solution I just read somewhere has the problem it need a kerberos ticket and wont work with foreign PCs over the internet, is there a way to solve that?

Best Regards