Possible to Use Apple's Backup 3.x Software with Mavericks/10.9.x?

As a longtime Dotmac/Mobile Me user, I used Apple's free software, Backup 3, forever and loved its simple interface and reliability.

After upgrading to 10.9/Mavericks, which no longer integrates Mobile Me membership, the Backup app (which I reinstalled) will only back up a paltry 100MB per backup because it needs to be unlocked using my now-defunct Mobile Me info, which cannot be entered anywhere.

Is anyone aware of a way to remove this limitation and restore full functionality to this legacy app?