No password is required when ProOffice populates XML files directly. This is independent of the protection settings.
The ProOffice AddIn for Microsoft Word supports documents which are working with forms and are having a form protection. In order to add values to such a document, the user must know the relevant password. The password set in the customizing will then be canceled temporarily and reset with the same password. All values in the form fields will remain.
In case the form is protected without a password, „no password" must be set as password in the customizing. This way the AddIn will cancel the form protection temporarily and reset it without password.
For documents without form protection, no special procedure is required (independent of customizing settings.)
Microsoft Word always requires a password in lower-case letters. ProOffice AddIn for Microsoft Word always converts the password into lower-case letters.
See OBJ | ProObjectLib | Customizing Manual for password settings.