Rebuilding kernel/system to a state "back-in-time"?

[Ewald Jenisch]

Hi,

Because of severe problems wrt. a third party app (TSM Backup - see my
previous post) I'm looking for a way to compile a kernel/system to a
state as it was several weeks ago.

To be specific I'd like to build my system/kernel using the
source-files of FreeBSD 6.2 as they were back on September 14, 2007.

In cvsup there seems to be a feature "date=..." that should be able to
accomplish this. Has anybody out there used it sucessfully? Is specifying

date=2007.09.13.23.59.00

together with the default-settings in my stable-cvsup-file 

*default host= <here comes my cvsup-host>
*default base=/var/db
*default prefix=/usr
*default release=cvs tag=RELENG_5
*default delete use-rel-suffix
*default compress
src-all         

enough?

Anything else to consider?

Thanks much in advance for any clue,
-ewald