To create the Outlook backup set you need to open Xopero and run the Backup set wizard by clicking on New backup set button in My backup sets tab.
In the Backup set wizard select Advanced copy and choose Outlook in What you want to backup? field. Don’t forget to define the backup set name.

In the Outlook panel what you need to do is to select Outlook data file. Click on Choose.. button and select location of .pst file.
After that choose Temporary directory. Click Save to create new backup set.