Memos stored on the computer when performing a HotSync?

Specifically, on a Mac running OS X using iSync 1.5.

I recently upgraded my Treo650's firmware (1.13).

Even though I followed the directions at Palm's website exactly, I've experienced loss of data (all my Memos are gone). I had to reset the Treo due to too little available memory to perform the upgrade in-situ. All my other data appears to have been restored successfully, except that I lost all category info for Calendar events.

I have been successfully syncing the Treo with the Mac since I bought it in March, before that I had a Treo600 for a little over a year, no problems syncing there either.

I'm hoping that my Memos are still on the Mac somewhere, and that I can restore them somehow. I've spoken to tech support at Apple and at Palm, but they just blame each other for the problem, or say they've never heard of it (they have now!).

If I can find out where Memos are normally backed up to, I might be able to restore them, or at least reenter the data.

iSync 1.5, OS X 10.3.7
using iCal 1.5.5, Address Book 3.1.2