api/user/v1.0/users NewLoginId functionality to rename a user does not work

Either this is not properly documented, or it does not work.

Post:

<batch xmlns="http://www.concursolutions.com/api/user/2011/02">
        <UserProfile>
                <EmpId>########</EmpId>
                <FeedRecordNumber>0</FeedRecordNumber>
                <LoginId>########@########.com</LoginId>
                <NewLoginID>########@########.com</NewLoginID>
        </UserProfile>
</batch>

Response:

<user-batch-result xmlns="http://www.concursolutions.com/api/user/2011/02" xmlns:i="http://www.w3.org/2001/XMLSchema-instance"><records-succeeded>0</records-succeeded><records-failed>1</records-failed><errors><error><EmployeeID>########</EmployeeID><FeedRecordNumber>0</FeedRecordNumber><message>Missing Required Field: Password</message></error></errors><UsersDetails/></user-batch-result>