i have an unneatly way to solve this problem.
i put an input textbox at the top of my <form>, and name it like "my_focusTextBox".
here is the code:
<input type="text" name="my_focusTextBox">
then I wrote these javascript just below "my_focusTextBox"
<script language="javascript">
document.getElementById("my_focusTextBox").focus();
document.getElementById("my_focusTextBox").style.display="none";
</script>
When the page is loaded, "my_focusTextBox" will first be set focus, not the FTB. this prevent the page from scrolling to the bottom.
I hope this will help you.