Blobs, REST, Firefox and Silverlight = Security Error

Question

Hello,
I'm trying to access Azure Storage blobs (via SAS string) from a Silverlight application. A clientaccesspolicy.xml is present in the $root blob container, allowing Silverlight access.
I've created a sample Silverlight application with just one button. The button executes the following code:
            var request = (HttpWebRequest)WebRequestCreator.ClientHttp.Create(new Uri("http://[mystoragename].blob.core.windows.net/[mycontainername]/[myfilename]?[sasString]"));
            request.Method = "GET";
            request.BeginGetResponse(r =>
                try
                    var response = request.EndGetResponse(r);
                    using (var s = response.GetResponseStream())
                        this.Dispatcher.BeginInvoke(() => MessageBox.Show(s.Length.ToString()));
                catch(Exception ex)
                    this.Dispatcher.BeginInvoke(() => MessageBox.Show(ex.Message));
            }, null);
Running this code on IE produces the expected result - the size of a blob uploaded to Azure Storage. Unfortunately, the same application, when ran in Firefox, produces a "Security Error" with no further indication of what might be wrong.
What could be the issue? Where should I even begin looking for one?
EDIT:
The same issue occurs in Chrome.
EDIT 2:
The SAME issue occurs when I try to download a file from a PUBLIC blob container (same code as above, only different URL). The public blob container also has it's own clientaccesspolicy and crossdomain XML files. Again - the code works in IE, but fails to function
in Firefox / Chrome.

Answer 1

I found a valid workaround.
I've created an ASHX handler on the web site which is hosting the Silverlight application. This handler basically "redirects" a HttpWebRequest to Azure Storage.
            var url = String.Format("http://{0}.blob.core.windows.net/{1}/{2}{3}", accountName, containerName, blobName, sas);
            var request = (HttpWebRequest)WebRequest.Create(url);
            try
                var response = request.GetResponse();
                context.Response.ContentType = response.ContentType;
                using (var stream = response.GetResponseStream())
                    stream.CopyTo(context.Response.OutputStream);
            catch
                context.Response.End();
Where the parameters used in building the url are passed as query string parameters to the ASHX handler. While not ideal (an ideal solution would be connecting from SL directly to Azure Storage), this works fast enough and doesn't seem to use much resources.