How do i save multiple backups in itunes?

[diesel]

Whenever i initiate a backup, it just seems to overwrite on top of the current backup. due to possible backup corruptions, i would like to back up every few days, and if the current backup is corrupt, be able to use a previous day's back up. right now, however, backups simply overwrite the current backup, it doesn't seem to create a new backup entry. how do i get itunes to create a completely new backup instead of writing over the current one. thanks