Incremental backups

[Esteban Dugueperoux]

Hi,

I want define a incremental backup policy with Rsync. But Rsync can only 
back up olds releases of modified files.
As I want back up on DAT tapes I would like to have a full backup and 
after some incremental backup with differences (modified or added files) 
from latest backup (full or incremental backup) and not backup of olds 
modified files.

How can I do this with Rsync?

Thanks.