I am not sure how MtTPlus is doing its job. To me, it seems like it is putting a one-time-only link in Start every time FF closes. Can you find a link to FF in "Start with Windows"? If so, in this new link, (?. I don't use it this way myself), you will see that MtTPlus has written
-turbo as parameter (for Vista). If you add a space and then type
-tray, Firefox will start minimized to system tray / notification area. This screenshot is from my Startup Delayer:
Thanks a lot for the link to your page. I will of course go and have a thorough look, but right now it is late night around here, and quite frankly I was only awake & up because I am an old man needing to go and wash my hands afterwards several times each night...