UpdateUser2: updates the specified user's settings.
o Return Type: GenericResult
o Parameters:
• AuthUserName: User name used to perform this function. Requires system
administrator or domain administrator privileges.
• AuthPassword: Password for the username
• DomainName: Domain for which to add the user.
• FirstName: First Name
• LastName: Last Name
• IsDomainAdmin: True if the user should be a domain admin
• MaxMailboxSize: Maximum size for the user mailbox (in MB)