I have a small VPS on which I host my own blog (which is really rather popular, the reason I bought the VPS) as well as the websites and blogs of a few friends. I'm not running a company, I don't have any sort of TOS - I host my friends' domains as an informal arrangement, a favour to save them having to pay for hosting.

Most of the time, this arrangement works well - the friends' sites use very little space and bandwidth. But recently, one of the people I host has been shoving up large AVI files which have been eating my paid-for bandwidth. He's taking the piss - I removed the files once and he simply re-uploaded them. I don't want to cancel his hosting as this'd be more trouble than it's worth - so is there any way under Plesk 8.0.1 (running on SuSE 10) of restricting this particular user from uploading certain filetypes, specifically AVI and MOV?

Failing that, a way of restricting him from uploading files larger than, say, 2MB would do.

Cheers in advance.