Hi,
[1] Do you need to be logged on graphical interface? (does the backup app has to be running graphically on the admin user?)
[2] Or just logging the admin user on background would do it? (in this case there would be no need to have the backup app opened graphically as it would just run automatically via job on the admin user, once it is logged)
[3] Another option would be to create a simple automatic service to run in background, for the admin user, to run automatically. (but also depends on how the backup app works)
I know how to do it the 3 ways above,
but you have to tell me more details about how the backup app works, so I can know which of the options above will serve better for your situation.