Welcome to Windows EightForums, DavidY. It's good to have you aboard.
So what your saying is that one would have to manually transfer the files from a XP backup source?
So (unless anyone knows different) I think that anyone wanting to do a clean Windows 8 install and transfer files from XP needs to use something other than XP Backup to do it; either copy files manually onto another disk, or use another backup utility that supports restoring of individual files or sets of files rather than restoring a whole disk image.
I think there is a case for using XP Backup for the scenario in which your Windows 8 installation fails and you want to go back to XP, especially if you're not doing a clean install, but otherwise I believe you need something else.
- Windows 8.1, 10