XMLHTTP greek encoding

[Nemlah]

Hello,
I am working on a site which utilizes PHP/JS and the new found XMLHTTP
frenzy to update dynamically.
WHile the whole mechanism works beautifull, i can't get to display
greek Characters correct (They show up as ?).
I tried following solutions to set the XML:lang or simple lang
parameter in the div to el, but that didn't help.. Greek text in the
surrounding page is showing up correct..
Here is the code i am using:
The JS File
if (!xmlhttp && typeof XMLHttpRequest!='undefined') {
xmlhttp = new XMLHttpRequest();
}

function loadFragmentInToElement(fragment_url, element_id) {
var element = document.getElementById(element_id);
element.innerHTML = 'Loading ...';
xmlhttp.open("GET", fragment_url);
xmlhttp.onreadystatechange = function() {
if (xmlhttp.readyState == 4 && xmlhttp.status == 200) {
element.innerHTML = xmlhttp.responseText;
}
}
xmlhttp.send(null);
}

The client PHP:
<?php
include ("../_mssqlconnect.php");
include ("get_login_data.php");
?>
<script>
function offerDetails(id)
{
loadFragmentInToElement('sc_ogdetails.php?ogid='+id, 'ogDetails');
}
</script>

//......

?>
<span lang="el" id="ogDetails" align="left"></span>

The server PHP:
<?php
include ("../_mssqlconnect.php");

//.......

echo "<div lang=\"el\">
<table class='sp_table' width=300 align=center>
<tr>
<td align=center><b>{here the greek Text which doesnt come
out right}<b></td>
</tr>
</table></div>";

ANy hints?
thanks