How to configure The Bat 1.39 for SMTP AUTH support.
First, Select the position "Properties" in the menu "Account"

Then, a window will appear:

Click on the "Transport" Field on the left. The Right side of the window will look like on the picture above.
Click on the "More" button.
Another window will appear:

Select "Perform SMTP Authentication (RFC 2554) option.
Now you have to decide if you want to use the same login/password that you are using for POP server (choose "Use POP server Login".
Click on "OK" , the window will close , click on the "OK button" in the Preferences window and now you have working SMTP AUTH support.