Plesk is running in Microsoft Active Directory environment. How to add domain prefix to Web Deploy "publishsettings" file before the customer downloads it?
This functionality is not yet implemented in Plesk. Please take part in our product improvement by referring to the following link: https://plesk.uservoice.com/forums/184549-feature-suggestions
The top-ranked suggestions are likely to be included in the next versions of Plesk.
For the time being, the file can be downloaded from Plesk > Domains > example.com > Websites & Settings > Web Deploy Publishing Settings and edited manually.