The problem

I have a page with a silverlight object. It attempts to retrieve XML from the page. But I am struggling with a security exception.

I have this code working brilliantly in WPF.

When using a website hosting a silverlight application with the same code, the user agent string of the HttpRequest object is null (and seemingly cannot be set). In fact there is no header information at all - this causes a security exception when attempting to make my asynchronous call.

The question

Why is the user-agent string (and header information) null in my silverlight 4 application when making an asynchronous call using HttpWebRequest?

Thanks in advance!