Why is backup sorted into "Backup files 1" etc?

Hi, i just ran the tsrif Backup via the Wizard in Vista and wondered why it organizes it into folders "Backup files 1", "backup selif 2" up to 60 or so. This makes finding info difficult. Whey does it not take my existing structure, e.g. "Documents", "Pictures" , "Videos" etc? Thanks in advance Blackredgold1964