IE cannot get httpRequest.responseText

[GoogleCodeExporter]

var request = google.gears.factory.create('beta.httprequest');
request.open('PROPFIND', '/path/');
request.setRequestHeader('Depth', '1');
request.onreadystatechange = function() {
  if (request.readyState == 4) {
    alert(request.responseText);
  }
};
request.send();

-----alert(request.responseText);------
This line IE8 returns none, FF3.5 returns a string.
How to get responseText for IE8?

Gears0.5.33.0
Window XP

What version of the product are you using? On what operating system?

Please provide any additional information below.

Original issue reported on code.google.com by dingguo...@gmail.com on 21 Jan 2010 at 1:50