After moving my backup data here is what I see in:
C:\Users\<User>\AppData\Roaming\Apple Computer\MobileSync
Note the link arrow over the folder icon in which also shows in the sidebar.
C:\Users\<User>\AppData\Roaming\Apple Computer\MobileSync\Backup
Showing the linked content that is really on D:
D:\MobileSync\Backup
The actual location of the data.
I can remove the existing junction by deleting the Backup icon shown in the first image, and then recreate it with the command:
MkLink /J "%AppData%\Apple Computer\MobileSync\Backup" "D:\MobileSync\Backup"
Have you got to the point where you see something similar in those locations? If not, what do you see at the moment?
tt2