Tricky, since most of these apps which can run in IE6 but not IE7 do bad things in JavaScript too. That means you can't just fix CSS issues in a proxy, because

Tricky, since most of these apps which can run in IE6 but not IE7 do bad things in JavaScript too. That means you can't just fix CSS issues in a proxy, because even if you could document every IE6 bug and how to fix it for IE7, the page could still change after it is loaded in the browser.