Can't restore differential backups of VMware VMs

Hi all

I use BE 2010R3. Backups are stored on external USB drive.  Also there is VMware evironment(vCenter 5.1/ESXi 4.1 and 5.1)

I arranged a dedicated policy wich includes full backup and differential backup jobs.

Full backup/restore works fine. Differential backups are success either, but issues are when I try to restore it. I make a restore job and select checkbox only for one of differential backups. But when I login into recovered VM I see only full backup state, but no changes since last full backup. I used to made a lot of tests, but nothing works. 

Please  guys, if someone faced with familiar problerm, contribute to my issue. Thanks