>We make a full backup on every Saturday and incremental backups on weekdays.
>We would like to keep also the incremental backups for a month. However, if
>I set the Backup Copy Group to retain the backups for 30 days, only the full
>backups will be preserved and the incrementals will be expired.
>Have anybody any idea?

Sadly, your site is undermining the intent of the TSM product by using like
a basic OS utility backup.  Your company could save a lot of money by
discontinuing use of TSM and just using a plain, old backup utility.
TSM offers so much more in modern methods that it should not be used that
way.

You can't have the same node:filespace:file bound to different policies.
Your alternatives, if you want to continue with the old regimen, is to
cause the same files to look different via different mounting or use of
Virtualmountpoint, or to use Archive and Backup in combination.

  Richard Sims, BU