You are setting it by the clock in the Surveyor tab, yes? That's only a preview of nightmode. In order to set a session to nightmode, go to the top menu in surveyor (these directions are for 06, btw, I don't recall the setup of Surveyor in 04) and click on the middle of the three buttons that are to the right of the pop-up menu. A box should pop up in the middle of the screen, with three options in the center. Click on the top option, and that will open a second box, and one of the options in the box should be "set time to _____ with ___ rate". (And on an unrelated note, if you deselect "show ingame help", it will make your screenies look better because the junction arrows then only appear if you mouseover them)