Modification complete.
Extra Instructions:
Each button now begins with:
<Button Username="AccountX" Password="PassX" LocalText="CharacterX" LocalTooltip="ServerX"
Change the Username and Password values on each button to match the account that the character (LocalText field) is on. For your search-and-replace convenience, the first 4 buttons are "Account1" and "Pass1", and the buttons 5-8 are "Account2" and "Pass2".
The window will still initially load with YOURPASSWORDHERE (or whatever you replaced it with) in the password field and the last account used in the Username field.
Enjoy.