How to support FileUpload in FireFox and Opera browser  Over SSL

I am able to uplaod and download the file in IE using Https. But in Firefox and opera it doesnot allows to upload a file.Upload request is done to a servlet. Sample request to uplaod a file used in code:
urlRequest = new URLRequest();
                                    
                        //Set the Request Header
                         reqHeaders = new Array();
                        reqHeaders.push(new URLRequestHeader("Content-Type", "multipart/form-data"));
                        urlRequest.requestHeaders = reqHeaders;
                       
                        //Data to be passed through request
                        urlVars = new URLVariables();
                        urlRequest.data = urlVars;
                        urlRequest.url = "/TestUploadl/uploadFile"+ ";jsessionid="+ ModelLocator.jSessionId;
                        urlRequest.method = URLRequestMethod.POST;
                        try
                        {
                             fileUpload.fileReference.upload(urlRequest);
                      } catch (error:Error)
                      {
                               Alert.show("err");
                          trace("Unable to upload files." + error);
                      }