How to save more than 1 windows backup image on a network drive

Original post on Microsoft Answers: How to save more than 1 windows backup on a network drive (not fully answered, I believe)

In Control Panel\All Control Panel Items\Back up and Restore (Windows 7), if I click Manage Space:

It says, "Your backups are being saved on a network. Only the most recent system image will be retained", and the Change Settings button is greyed out:

Is it possible to change the backup settings so that more than 1 backup image is stored on the network, ideally 4 or 8?

Thanks,

Steve