Your data is not automatically backed up by Microsoft ActiveSync.
However, when your device is connected to your desktop PC using ActiveSync, you can copy-and-paste files from your device to your desktop PC. If you installed StyleTap onto memory of your device (versus an external card), then the subdirectory path that you need to copy from is
First make sure that you terminate StyleTap so that all the data files are up-to-date. The easiest way to do this is to bring up the on-screen keyboard and type Ctl-Q.
You access the source directory from your desktop PC by going to
My Computer -> Mobile Device -> My Windows Mobile-Based Device -> Program Files -> StyleTap -> db. Then copy all the files in this subdirectory and paste them to a subbdirectory on your desktop PC and you will have a complete backup of all the Palm OS databases.
All the files with the stp file extension are actually in Palm prc and pdb file formats so that if you renamed them with prc or pdb file extensions, you could install them on a Palm OS device if you ever wanted to.