Plesk backup doesn't split and upload

[ProWebS]

Hello,

I've tries 3 times to make a backup of the whole server and data,

I click on "Create multivolume backup Volume size" and use 1024MB to create 1 GB (the total backup is 11GB)
so that I be able to download it through plesk.

the backup is completed (Comments: Server backup. Creation date: Feb 20, 2013 03:56 PM)
I still cannot download it through plesk
and when I visit C:\Program Files (x86)\Parallels\Plesk\Backup\
I dont see any backup files only, and If I visit C:\Program Files (x86)\Parallels\Plesk\Backup\clients\
there are folders with each name of the client's ...
so I can't find anywhere the whole backup splited in 11 files (11GB splited to 1024MB).

Any ideas?