Hi Karla, have you tried deleting the property completely and recreating it with the new value? By default, you should be able to enter anything you want in the source attribute for outbound mapping, including static values. If the problem persists, and the behavior that you're seeing is that the value gets flipped back to "Main" as soon as you change it and tab out, without getting any errors or warnings, I would recommend to make sure that there are no automation scripts that could be interfering and potentially overwriting the value.