Storage of encryption keys

I need to advise on the security of the password-protected backup process in B&R V.10 and 11.
I've noticed that once a password is entered to a backup plan, then repeat activation of the plan pulls the password without asking to reneter it.
Where and how is this password kept in the archiving computer? Since no credentials are needed to run a subsequent archiving job, I would assume that it is kept in the clear?
The answer will help to see how strongly one needs to protect his archiving computer against a possible password compromise.