KDE Logon Window (User List)

I have a silly question to ask. When you first start Linux you are presented with the logon Dialogue box. The first half of this box shows the user you defined when installing Linux - Which is fine. I have enabled the supplied oracle account, and I would like this to appear as a selectable icon in this window, I would also like to add root. Can anyone please tell me how I do this? Many Thanks Mike