Wijmo vault progress bar


im using vault 3.0 for file uploading but i have some problems with progression bar.
i can upload files to my server(amazon S3) but the progression bar is not sync when uploading to my server.
I upload one or more files, the progression bar will go 0% to 100%. After that it will uploaded to my server.
But the result that i want is , the progression while file is uploaded to my server.

Can anyone help me with this problem?
thank you in advance.