After copy script to edit drives' Spotlight Comments?

[techno]

Hi there,
I'm loving SuperDuper! and I am wondering if it is possible to use a shell script (or any kind of code) to edit the Spotlight Comments (in Get Info) of the source and target drives with the following info: "Last backed up using SuperDuper! on [date] at [time]." If possible, I would want the script to preserve any text in the Spotlight Comments that was not made by that script earlier. Is this possible? Let me know if I can be more specific to help you get an understanding of what I want. Thanks!