Google AdWords/AdSense ClickFraud

I'm having some serious problems with ClickFraud on my site.

When I activate my AdSense campaign, not much more than 5 minutes go by before they are all over it.. Multiple clicks from the same Internet IP's in Malaysia, Poland, Hongkong etc. (I tried to exclude certain countries in my AdSense account, but they seem to go through proxies, so its not much use)..

Tried just now and within 2 minutes I had around 20 clicks, which were clearly fraudulent (they seem to use some kind of tool - no pictures on the site were loaded according to my log). I guess that was around €20, which went up in smoke there. The super-duper top secret internal Google clickfraud prevention system, which is supposed to deduct the invalid clicks at the end of the month, only seems to catch an extremely small fraction of the clicks, but not nearly enough. I can't see which clicks I actually pay for in the invoice from Google, so it's a bit hard to say.

AdSense is completely useless to me as it is now, so anyone got a tip or two to get around this annoying problem. Google Support isn't much help either - "We'll detect the invalid clicks", they say, but that's not what I see.

Kind regards
Bjørn