Tonight I have added a nice little feature to ModelConverterX again (it will be in the 1.2 development release tomorrow). You might wonder what it is? You can now choose to render your object in day or night view. The night view allows you to preview the night textures. Here is a little screenshot of one of the default objects.
It is not yet finished, since I just display the night texture now. Whether it is a nightmap or a lightmap is not yet taken into consideration. So that gives some room for future improvement. But this will allow you to check how the object would look during the night.