Just for the record it was the browser passing the form params as Latin unless there was a character that couldn't be represented in Latin. Then it would do as it was told and pass it as utf-8
Can you show either the actual webpage with the form or a simplified test case of it? Because I'm still pretty sure browsers don't do that if the page is correct. Certainly not Firefox, which I also use and which behaves just fine in my own UTF-8 applications, even if I only submit ASCII and umlauts that could be represented in Latin1, but no characters > 256.
BTW, you can check what exactly Firefox submits by using the very useful LiveHTTPHeaders extension from http://livehttpheaders.mozdev.org. And/or you could check browsers against one of my UTF-8-capable applications at http://www.mwforum.org.
