Everything is working as it should, until here. According to http://msdn.microsoft.com/workshop/author/dhtml/reference/objects/button.asp:
When the BUTTON element is submitted in a form, the innerText value is submitted.
This element is available in HTML and script as of Internet Explorer 4.0.
Internet Explorer fucks it up here :-) Way bad it's true (tested in IE6 SP2).
Sometimes it's handy to use the
button in stead of the
input, cause the submitted part of an
input is the same as it's caption. So you have to change the server side as well if you change your client side code.