I believe the last camera added will be listed always at the top.
Short of re installing each camera, starting with 5, 4, 3, etc., I don't believe you can sort the cameras on Mydlink or Mydlink Lite. I use LivePro Cams app from the iTunes store (I think it was two bucks) on my iPhone and you can sort them anyway you want. However, using the third party viewer you would have to give each camera it's own port number and forward those in your router.
The biggest advantage of this app is that you can view all your cams simultaneously in thumbnails or individually, your choice.