Hello Friends...
This is my personal experience that the .xml file generated which is to be digitally signed is only to be uploaded with the use of Internet Explorer.
I was uploading one through Google Chrome and was not able to sign.
I tried to solve this querry by applying every means possible.
But the last result i got is that i was uploading it with Google Chrome which is not supported with it and tried it with Internet Explorer and i was succesful in that attempt.