Did some quick reading (TSM Online Help) - looks like it can indeed be done,
with exceptions and notes worthy of your attention.  Here's an exerpt from
the text: incremental command

Incrbydate
Important: It is recommended that if you have limited time during the week
to perform backups, but extra time on weekends, you may want to maintain
current server storage of your workstation files by performing a partial
incremental backup on weekdays, and a full incremental backup on weekends.


The incrbydate option is used with the incremental command to backup up new
and changed files with a modification date later than the last incremental
backup stored at the server, unless the file is excluded from backup. Files
added at the client after the last incremental backup, but with a
modification date earlier than the last incremental, are not backed up

An Incremental-by-date updates the date and time of the last incremental at
the server. If an incremental-by-date is performed on only part of a file
system, the date of the last full incremental is not updated, and the next
incremental-by-date will back up these files again.

Both full and partial incrementals back up new and changed files. An
incremental-by-date takes less time to process than a full incremental, and
requires less memory. However, unlike a full incremental, an
incremental-by-date does not maintain current server storage of all your
workstation files because:

It does not expire backup versions of files that are deleted from the
workstation.
It does not rebind backup versions to a new management class if the
management class has changed.
It does not back up files with attributes that have changed, unless the
modification dates and times have also changed; for example:
NT security information



It ignores the copy group frequency attribute of management classes.
Syntax

>>-INCRbydate--------------------------------------------------><


Parameters

There are no parameters for this option.

Examples


Command line:
dsmc incremental -incrbydate
***********************************8

Good luck!