I think I may have discovered something:
If you create a new MBM document, the saved settings are saved. In other words, File>New, take a look at the settings in the new document. Mine defaulted to my "created" account. In addition, when I went to send a quick test to myself, I was not asked to enter a password.
The problem seems to be with MBM documents created in some earlier version of MBM. Ussually when I create a new email document, I do a Save-As from another MBM document.
It looks like the way to do this is to first create a new document and then go from there.
Can anyone else confirm my new document theory?
Jonathan