Back Up Software Update for iPod Touch

[ex2bot]

Here's a question I haven't seen asked or answered: How do I back up the $20 software update for my iPod touch? Yes, I was a sucker and bought it (and glad I did). Where does the update live so I can back it up?

I am using Time Machine, but I'd like an alternate method.

D

*EDIT* Here's a support article that's interesting, but it doesn't seem to answer my question:
http://support.apple.com/kb/HT1766

[VirtualTracy]

Does this apply to your iPod Touch (http://support.apple.com/kb/HT1414), dktrickey?

[ex2bot]

Thanks, VirtualTracy. But I don't see anything about backing up the extra, optional $20 iPod touch software update that included Mail, Stocks, Weather, Google Maps, and so on. I don't want to lose the update and have to pay again.

Maybe that's not even an issue. I'd like to find out for sure.

D